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Quick Search     Adv Search   2024 Vol. 34, No. 02 Published: 2024-04-10   1 Progress on manufacture of powder metallurgy HSS/tool steels and development on their applications Hot! YU Yang，XU Shenghang，LIAO Jun DOI: 10.13228/j.boyuan.issn1006-6543.20230174 HSS and tool steels perform specially in their high mechanical and thermal properties such as high strength and toughness, high hardness, high wear resistance, and good heat resistance, which are widely used in in‐ dustries such as metalworking, plastic injection molding, and automotive manufacturing, etc. Conventionally, they are prepared by traditional casting and forging process, which always introduce compositional segregation and coarse carbides in their microstructure. These micro defects are difficult to eliminate through conventional process‐ ing methods such as forging, leading to the deterioration in material properties. The powder metallurgy process pro‐ vides an uniform microstructure, fine dispersive carbides, and high alloy composition, which allows for the manu‐ facturing of complex shapes and structures of the final products. Through this approach, the tool and die products have the advantages of higher performance, higher precision, and longer life, and have important applications pros‐ pects in the high-end manufacturing industry. In this work, a comprehensive review of the production technologies and applications of powder metallurgy HSS and tool steels are provided. Besides, the technological innovations in the industrial production, the manufacture methods, and the microstructural properties of powder metallurgy HSS and tool steels are discussed in details. Furthermore, the classifications and applications of these materials, offering an outlook on the future development trends in powder metallurgy HSS and tool steels were summarized. 2024 Vol. 34 (02): 1-10 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 4 ) 11 Study on high performance Fe-Al2O3 composites produced with Bayan Obo Ore by carbothermal reduction Hot! CHEN Yuxin，XU Wensheng，WANG Ning DOI: 10.13228/j.boyuan.issn1006-6543.20230021 In this study, the Fe-Al2O3 composite was prepared by carbothermal reduction method with Bayan Obo iron concentrate as main raw materials, meanwhile, the activated carbon was added as reducing agent. The effects of different amounts of reductants on the reduction process, microstructure and properties of composites were stud‐ ied. The results of XRD show that sample C1 is mainly composed of Al2O3, Fe, spinel and a small amount of iron oxide due to low reducing agent content. The diffraction peaks of spinel and iron oxide disappear with the increase of reducing agent dosage. Furthermore, there is a small amount of anorthite contained in the samples C1-C4, which gradually decreased with the increase of reducing agent dosage. SEM analysis shows that the metal phases are uni‐ formly distributed in the alumina matrix in granular form, and a small amount of glass phases exist at the grain boundary of alumina. Fracture mechanism analysis shows that the metal phase absorbs energy through plastic de‐ formation to improve the mechanical properties of the composites. The optimal properties of the sample are as follows: density of 4.12 g/cm3, porosity of 0.62%, linear shrinkage of 17.55%, bending strength of 308 MPa, hardness of 13.02 GPa, acid resistance of 93.55%, alkali resistance of 98.85%. This study provides a low-cost and cleaning process for the preparation of high performance composite materials from natural minerals. 2024 Vol. 34 (02): 11-20 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 21 Microstructure and properties of porous copper foams prepared from different copper powders Hot! FANG Qingqing，CHEN Ruizhi，CHEN Pengqi，CHENG Jigui DOI: 10.13228/j.boyuan.issn1006-6543.20230029 Porous copper foams were prepared by loose sintering water-air combination atomization copper pow‐ der and electrolytic copper powder at 700~900 °C for 120 min, respectively. Influence of the raw copper powders and the sintering temperature on the porosity, pore structure and properties of the sintered porous copper samples were investigated. The results show that with the increase of sintering temperature, the porosity of sintering sam‐ ples decreases. The porosity of sintered samples prepared from water-air combination atomized copper powders is about 30%-60%, with uniform morphology of pores, while the porosity of the sintered samples prepared from elec‐ trolytic copper powders is about 40%-70%, with irregular pore morphology. At the porosity of 50%, the initial yield strength and thermal conductivity of the sintered porous copper samples prepared from the atomized copper powder are 20.18 MPa and 59.13 W·m/K, respectively, while for the samples prepared from the electrolytic copper powder are 14.44 MPa and 41.32 W·m/K respectively. The sintered copper foam prepared from the atomized pow‐ der own better mechanical and thermal properties with similar porosity, which can be ascribe to the pore formation mechanism during the loose sintering process. 2024 Vol. 34 (02): 21-27 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 3 ) 28 Development and analysis of MlM 17-4PH stainless steel small module gear Hot! LI Jie，YE Dequan，QIU Yaohong DOI: 10.13228/j.boyuan.issn1006-6543.20230010 The use of metal powder injection molding (MIM) technology to produce small metal parts with com‐ plex geometric shapes, especially for transmission parts with similar and repeated features, such as small module gears, had certain advantages. As for the selection of metal gear materials, stainless steel 17-4PH could be used in‐ stead of MIM technology. The mechanical properties and corrosion resistance of this material are superior to those of traditional machined gears. In this paper, according to the characteristics of stainless steel 17-4PH, gears were made by MIM process and heat treated under different conditions (after sintering, H900, H900+annealing). After quality testing, there is a slight change, which is similar to the results of traditional hot rolled plates. MIM process could make complex gears, maintain the excellent dimensional accuracy of stainless steel 17-4PH, and improve me‐ chanical properties. 2024 Vol. 34 (02): 28-34 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 35 Numerical simulation of temperature field and stress field in the lapping of W6Mo5Cr4V2 and Ni60A-WC dissimilar materials by axial laser cladding Hot! XIE Weipeng，XU Mingsan，WANG Jianguo，ZENG Shoujin，WEI Tieping DOI: 10.13228/j.boyuan.issn1006-6543.20220170 Through the temperature field and stress field distribution of the high-speed steel (W6Mo5Cr4V2) and Ni60A-WC cladding lap on the axial plane, the influence of different laser power, lap sequence and lap ratio on the temperature field distribution and the stress distribution of dissimilar materials along the specific path of the lap cladding section are studied. The temperature field and stress field in the process of lapping cladding are simulated with ansys software, and the single factor variable method is used to simulate the parameters; The simulation re‐ sults of temperature field are verified by using infrared thermometer. The laser power has the greatest influence on the temperature field during the lapping process. With the increase of the laser power, the influence of the lapping sequence on the temperature field decreases. When the two lapping powers are 2 000 W, the maximum temperature first increases and then decreases with the increase of the lapping rate. When the lapping rate is 40%, the maximum temperature is the maximum. At the same time, the axial and radial stresses at the edges of the lapped coatings are compressive forces. The circumferential and radial stresses in the overlap area are tensile forces. Due to the difference of thermophysical properties, the anisotropic stress of high-speed steel coating is larger than that of nickel based tungsten carbide coating. The temperature of each observation point was verified by experiment and simula‐ tion, and the maximum temperature error was 5.66%, which was in line with the expected value. 2024 Vol. 34 (02): 35-43 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 44 Role of contour scanning speed on the lateral surface quality of TC1 alloy printed by selective laser melting Hot! HU Jiaqi，DONG Dingpin，CI Shiwei，CAI Xiaoye，XIE Suijie，CHENG Zonghui DOI: 10.13228/j.boyuan.issn1006-6543.20230028 Selective laser melting (SLM) process is one of the key three-dimensional printing technologies, which has been widely applied into the manufacturing of components with geometrically complex structures. Most of the selective laser melting printed components should subject to machining operation to satisfy the requirement of surface quality, like polishing and grounding. It is attractive that the comparatively low demand of printed component surface quality can be met through tailoring the parameters of printing processes. The subse‐ quent machining procedure can be thus reduced with shortened production cycle and optimized cost-effectiveness of manufacturing. So it is vitally important to elucidate the effect of SLM parameters on the surface quality of printed components. In the current study, a series of distinct contour scanning speed were utilized to prepare SLMed specimens of TC1 titanium alloy. The sections of specimen lateral surface were observed by Axio Oberver 3M microscope. The printing defects in the lateral near-surfaces of specimens were also characterized. The corresponding outline of near-surface boundaries were further extracted and processed. The data of outline was then statistically obtained to quantitatively calculate the roughness of the printed specimen surfaces. The Vickers hardness variation in the area within the range of 0.05 to 0.8 mm away from the lateral surface was measured by Wilson VH3100 hardness tester. It is found that the roughness (Ra) of the SLMed specimens lateral surfaces increases from 8.09 μm to 12.27 μm with the rise of contour scanning speed, which can be primarily attributed to the balling behavior and incomplete melting of powder adherent with the surface. To be specific, a large amount of air pore defects form around the near-surfaces of the components due to the keyhole effect of melted powders. The air pores mainly distribute in the areas 80 μm to 130 μm away from the near-surfaces. The size of these air pores varies from 20 μ m to 50 μ m. On the other hand, unfused defects occurred in the nearsurfaces of specimens can be ascribed to the low energy density at high contour scanning speed (900 mm/s). The unfused defects locate at the areas 100 μm to 115 μm away from the near-surfaces. The dimension of the unfused defects long axis varies from 10 μm to 50 μm. In addition, relatively lower contour scanning speed leads to the increment of energy density. The cooling rate of the melting pool in the contour area consequently reduces. As a result, the hardness of the near-surfaces decreases. Therefore, it can be deduced that high contour scanning speed benefits to the maintaining of hardness around the near-surfaces areas. On the basis of the above research results, it is thus concluded that tunning the contour scanning speed of selective laser melting process can effectively amelio‐ rate the lateral surface quality of the SLMed specimens of TC1 titanium alloy. While a moderate contour scanning speed is proposed as an appropriate printing parameter. 2024 Vol. 34 (02): 44-48 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 4 ) 49 Analysis of flow field and particle characteristics of atmospheric plasma spraying Hot! ZHANG Yong，GUO Longlong，JU Luyan，WU Heng DOI: 10.13228/j.boyuan.issn1006-6543.20230038 The thermal swimming force and pressure gradient force of particles in the process of plasma spraying were considered, and the flow field distribution and particle characteristics in the process of atmospheric plasma spraying were studied. The results show that in pure argon, the maximum temperature of atmospheric plasma spray‐ ing flow field is 14 000 K, and the maximum velocity is 470 m/s. The maximum temperature of flow field under ar‐ gon-hydrogen mixing condition is 30% higher than that under pure argon condition. The temperature field is not symmetrical along the Z axis, but humped. When the carrier gas flow rate is 5 L/min, the particles can be sent into the center of the plasma jet to obtain sufficient kinetic energy and thermal energy of the flow field. With the in‐ crease of carrier gas flow, particles pass through the flow field. When the carrier gas flow rate is 3 L/min, the parti‐ cles fly above the plasma fluid, which is not conducive to heating acceleration. In pure argon, the maximum veloci‐ ty of the particles reaches 271 m/s and the maximum temperature is 4 000 K. In this paper, the optimal spraying dis‐ tance is 80 mm. 2024 Vol. 34 (02): 49-55 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 56 Influence and optimization of ultra-fine classification grinding disc structure on flow field in crushing chamber Hot! QI Xijuan，JIANG Lei，QIN Zhiying，ZHAO Jifu，ZHAO Yuejing DOI: 10.13228/j.boyuan.issn1006-6543.20230083 In the processing of non-metallic materials, the ultra-fine classification mill is an ultra-fine powder prep‐ aration equipment which integrates ultra-fine grinding and classification, whose principle is to make use of the high-speed rotation of the grinding chamber. The material in the grinding chamber has a fierce impact and collision with the blade on the grinding disc, and it is crushed under the dual action of machinery and air flow. The study of the mechanical structure, flow field distribution and its influencing factors in the crushing chamber has important engineering significance to ensure the ultra-fine grinding particle size and improve the grinding efficiency. In this paper, the flow field of ultra-fine classification mill is numerically simulated by computational fluid dynamics soft‐ ware Fluent, and the flow field distribution is observed by single factor experiment. The experimental results show that the change of the number and width of the blade on the grinding disc has little influence on the air flow veloci‐ ty in the grinding chamber, but has a great influence on the air pressure and axial velocity in the grinding chamber. The movement of the material entering the grinding chamber is not fully dispersed to the grinding area, which is easy to cause agglomeration. The structure of the grinding disc in the grinding chamber is optimized by using the simulation results, and the optimization results are verified. 2024 Vol. 34 (02): 56-62 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 0 ) 63 Effect of tungsten powder particle shape on the emission properties of the barium-tungsten cathode Hot! WANG Minghui,HU Ke，YANG Shisong，WU Renjun，ZHANG Fangyang，LIN Bo DOI: 10.13228/j.boyuan.issn1006-6543.20230033 Porous W matrixes for dispenser Ba-W cathodes were prepared by metal injection molding (MIM) us‐ ing W powders with different particle shapes as raw materials. The influence of the powder particle shape on the pore characteristics of porous W matrix and the emission properties of the Ba-W cathode was studied. The results show that although the particle size distribution of spherical W powders （SW）and narrow particle size distribution W powders （NPW）powders are basically the same, the NPW powders have a higher specific surface area than SW powders for the higher“Outgrow”and Concavity value. The pore-specific volume of porous W matrix prepared by two different powders is almost the same, compared with the PNPW matrix, the PSW matrix has higher open porosity and larger average pore size. However, the sinuous pore channels formed by the irregularly shaped W powder parti‐ cles and sintered necks inside the P NPW matrix have a higher pore-specific surface area, which results a higher con‐ tact area between the impregnants and the W powder particles. Therefore, more barium atoms are reduced in the same time, which make the coverage of the active barium atoms on the cathode emission surface higher, reduces the cathode work function, and the emission current density of the cathode is improved. 2024 Vol. 34 (02): 63-68 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 3 ) 69 Effect of Al on microstructure and mechanical properties of medium entropy alloy in VCoNi system by laser melting deposition Hot! YU Hui，ZHAO Lin，PENG Yun，CAO Yang，MA Chengyong，TIAN Zhiling DOI: 10.13228/j.boyuan.issn1006-6543.20230196 VCoNi and Al 7(VCoNi)93 medium entropy alloys were manufactured by Laser Melting Deposition （LMD）, and the microstructure and mechanical properties of the medium entropy alloys were investigated. The re‐ sults show that the VCoNi medium entropy alloy is a single FCC solid solution structure, while the Al7(VCoNi)93 medium entropy alloy is an FCC+BCC duplex solid solution structure, and the Al element promotes the formation of BCC structure. The influence of Al on the mechanical properties of VCoNi alloy is significant, which increases the hardness and strength of the medium entropy alloy, but decreases the ductility and toughness. Compared with VCoNi, the microhardness of Al7(VCoNi)93 increases from 317HV0.1 to 370HV0.1, the tensile strength increases from 964 MPa to 1 138 MPa, and the impact toughness decreases from 88 J/cm2 to 60.5 J/cm2 at room temperature. 2024 Vol. 34 (02): 69-74 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 75 Design, fabrication, microstructure and properties of Cu-(graphene/6063Al) composites Hot! ZHANG Kemeng，LIU Pei,WANG Jie，HOU Bo，LIU Zhenwei，GAO Yan DOI: 10.13228/j.boyuan.issn1006-6543.20230017 In this paper, the Cu-6063Al composites and 0.5%, 1.0% content Cu- (graphene/6063Al) composites were fabricated by cold isostatic pressing + vacuum hot pressing sintering + hot extrusion method using 6063Al al‐ loy powders, graphene nanosheets and pure Cu sheet with a thickness of 2 mm as raw materials. The phase analy‐ sis, microstructure, fracture characterization and mechanical properties of the three composites were investigated by XRD, SEM and tensile testing machine. The metallurgical composite of graphene /6063Al and Cu can effective‐ ly inhibit the diffusion of Al atoms, and thus inhibit the formation of Al4Cu9, Al2Cu 和 AlCu intermetallic com‐ pounds at the Cu/Al interface in Cu-6063Al composites. The tensile strength of 0.5% and 1.0% Cu- (graphene/ 6063Al) composites is 76.9 MPa and 101.3 MPa, which are 40% and 83.8% higher than that of Cu-6063Al com‐ posites respectively, and the elongation is decreased. The Cu-(1.0%graphene/6063Al) composite possess excellent mechanical properties, due to a small amount of brittle phase at the Cu/Al interface and more, smaller, deeper dimples, wider tearing edges and tighter distribution of graphene nanosheets near the interface layer of Al side. 2024 Vol. 34 (02): 75-80 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 4 ) 81 Influence of BaO doping on the sintered properties of magnesia-alumina Hot! ZHENG Haonan，ZHANG Wangnian ，FANG Yan，DENG Ning，XU Huan ，ZENG Haiyan DOI: 10.13228/j.boyuan.issn1006-6543.20230032 With magnesium hydroxide and alumina as raw materials, magnesium alumina spinel was synthesized by solid phase sintering. The effect of additive BaO on the sintering density of magnesia alumina spinel was stud‐ ied. The effects of additives on the phase composition, sintering property and microstructure of the samples were analyzed by XRD and SEM. The results show that the addition of BaO can increase the bulk density and linear shrinkage of Mg-Al spinel after sintering. At the same time, the apparent porosity can be reduced and the sintering property can be improved. With the increase of additive BaO, the granules of magnesia-alumina spinel increase first and then decrease. The linear shrinkage rate, apparent porosity and volume density of ?20 mm ×20 mm cylin‐ drical samples sintered at 1 600 ℃×3 h are 6.81%, 54.30% and 1.65g/cm3 without adding BaO. When the amount of BaO is 0.5%, the linear shrinkage rate, apparent porosity and volume density of ?20 mm ×20 mm cylindrical samples sintered at 1 600 ℃×3 h are 6.81%, 54.30% and 1.65 g/cm3 respectively. The linear shrinkage rate can reach 12.07%, the volume density can reach 1.80 g/cm3, and the apparent porosity can reduce to 47.56%. There‐ fore, when the additive content is 0.5%, the sintering property of MgAl2O4 is the best. 2024 Vol. 34 (02): 81-85 [Abstract] ( 4 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 86 Influence of phosphating process on magnetic properties of FeSiCr soft magnetic composites Hot! HE Zhengye，LUO Jian，AN Jing，XU Lihong，MU Xing，GUO Shihai DOI: 10.13228/j.boyuan.issn1006-6543.20220203 In this study, the surface modification treatment of FeSiCr alloy powder was carried out with zinc-man‐ ganese phosphating solution. Vibrating sample magnetometer, impedance analyzer and soft magnetic material AC test device were used to analyze effects of the content of zinc-manganese phosphating solution on saturation mag‐ netization of FeSiCr magnetic powder, effective permeability and power loss of FeSiCr magnetic powder cores. The results show that with the increase of the concentration of zinc-manganese phosphating solution, the saturation magnetization of the composite magnetic powder core gradually decreases, the power loss first decreases and then increases. When the concentration of zinc-manganese phosphating solution is 25%, the effective permeability is 39.5, and the power loss is only 103.6 W·kg-1 (100 kHz, 50 mT). 2024 Vol. 34 (02): 86-90 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 3 ) 91 Study on structure and performance of PCBN super-hard tool materials for car gear parts Hot! SUI Liming，LI Kun，SONG Haisheng，LIU Gang DOI: 10.13228/j.boyuan.issn1006-6543.20230030 PCBN (polycrystalline cubic boron nitride) superhard tool materials were synthesised under high tem‐ perature and high pressure conditions using CBN/Ti/Al as raw materials. The effects of the synthesis pressure on the flexural strength, wear resistance and interfacial morphology of the PCBN composites were investigated. The results show that the flexural strength and wear resistance of the PCBN composites increases as the synthesis pres‐ sure is increased. The bonding interface between the cemented carbide matrix and CBN is analysed by scanning electron microscopy. The test results show that increasing the synthesis pressure can improve the interfacial bond strength of the PCBN material, reduce the occurrence of delamination and cracks, and improve the yield of the syn‐ thesised product. Also, within the pressure range at 5.5-7 GPa, PCBN has better flatness, less CBN thickness differ‐ ence and higher product utilisation in cutting. The performance of the synthesised tool material at 7 GPa is relative‐ ly close to that of Sumitomo BN700 in machining gear parts, with good market prospects. 2024 Vol. 34 (02): 91-96 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 5 ) 97 Effect of La 2O3 doping methods on the properties of MR14 plates Hot! WANG Guangda ，ZHANG Danhua，XIONG Ning，KUANG Chunjiang DOI: 10.13228/j.boyuan.issn1006-6543.20230188 La 2O3 can refine grain size, pin dislocations, and improve the strength of molybdenum. Rhenium can re‐ duce the ductile brittle transition temperature of molybdenum, improve its strength and elongation performance. In order to fully utilize the fine grain strengthening effect of La2O3 and further improve the mechanical properties of MR14 sheet, this article studied the effect of La2O3 doping methods on the properties of MR14 alloy through three powder mixing processes: solid solid doping, solid liquid reduction doping, and liquid liquid doping. Research has shown that both solid-liquid reduction doping and liquid-liquid doping can refine grain size, improve microhard‐ ness and room temperature mechanical properties, with small performance differences and a 50% higher elongation than solid-liquid doped plates. 2024 Vol. 34 (02): 97-101 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 102 Effect of Ti on microstructure and wear resistance of 304L laser cladding coating for vehicle Hot! ZHANG Liansong，XU Guojian，XUE Yuanhui DOI: 10.13228/j.boyuan.issn1006-6543.20230059 In order to improve the wear resistance of 304L stainless steel for vehicles, 304L coating and 304L-5% Ti coating were prepared on the surface of 304 stainless steel by laser cladding. The effects of Ti on the phase com‐ position, morphology, elemental distribution and wear behavior of 304L stainless steel coating were studied. The re‐ sults show that the phase composition of 304L-5% Ti coating is α-Fe and γ-Fe. A small amount of TiC particles are generated in the coating. The surface microhardness of 304L coating and 304L-5% Ti coating are (187±7.8)HV and (270±8.9)HV, respectively, and the introduction of Ti element increased the microhardness of the coating by 45%. The average friction coefficients of 304L coating and 304L-5% Ti coating are 0.756 and 0.649, respectively, and the specific wear rates are 8.03×10-5 mm3/N·m and 5.41×10-5 mm3/N·m, respectively. The wear rate of 304L-5% Ti coating is reduced by 35%. The wear mechanism of 304L-5% Ti coating is adhesion wear and abrasive wear. 2024 Vol. 34 (02): 102-106 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 4 ) 107 Research progress on the influence of friction components on the properties of copper-based friction materials Hot! WU Shen，SI Qufan，JIANG Aiyun，DONG Zhenzhen，LIU Jianxiu，ZHANG Qian DOI: 10.13228/j.boyuan.issn1006-6543.20230031 The braking system is the key and core component of the safe operation of high-speed train. Copperbased powder metallurgy friction material has become the preferred material for high-speed train brake plate because of its characteristics of uniform structure, high wear resistance, high hardness and stable friction coefficient, and can give full play to the advantages of matrix material, friction component and lubrication component and their synergies. With the continuous increasement of train speed, the temperature of friction braking has become higher and higher, which puts forward higher requirements on the high temperature stability and oxidation resistance of friction materials. This paper primarily discusses the effects of the types of friction components and adding methods on the structure and friction properties of copper-based powder metallurgy friction materials, and the bonding effect between friction components and matrix and the friction and wear mechanism are summarized and reviewed. The future development trend of copper-based powder metallurgy friction materials is prospected. 2024 Vol. 34 (02): 107-115 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 3 ) 116 Research status of 3D printing materials and technology in aerospace field Hot! LI Jing，YAN Feng，WANG Jin，DANG Xiaoming，WANG Yuqing，HE Kai DOI: 10.13228/j.boyuan.issn1006-6543.20220219 The research status of 3D printing technology in the aerospace field was summarized in this paper, the characteristics of geometric components with complex structures and topology optimization processed by 3D print‐ ing technology were introduced. The development of 3D printing preparation technology applied in the aerospace field at home and abroad was emphatically described, including metal based materials, directed energy deposition technology (DED), powder bed fusion molding (PBF) and post-processing technologies, as well as manufactured aerospace components. The advantages-disadvantages of 3D printing technology in the aerospace field were sum‐ marized, and technical improvement and research direction were prospected. 2024 Vol. 34 (02): 116-126 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 4 ) 127 Research status on titanium alloy and titanium powder for 3D printing Hot! LI An，LUO Cheng，YANG Bowen，ZHANG Peng，ZHAO Xiaohao，LAI Yunjin DOI: 10.13228/j.boyuan.issn1006-6543.20220232 3D printing is a new type of manufacturing technology, which is widely applied in the field of aero‐ space, medical treatment, automobile, ships.Titanium alloy is an important part of metal 3D printing system due to its excellent properties such as light weight, high specific strength, good corrosion resistance and excellent biocom‐ patibility. The performance requirements of titanium materials and main preparation methods of powder of 3D printing were briefly described. The characteristic of GA and PREP preparation technique were compared, and the reason for the difference of GA and PREP preparation technique were explained emphatically. At last, research directions and application prospects were expounded. 2024 Vol. 34 (02): 127-133 [Abstract] ( 4 ) HTML (1 KB)  PDF  (0 KB)  ( 3 ) 134 The design development and application of intelligent high-precision high-speed powder forming machine Hot! FENG Jinyu，LUAN Changping，PAN Xueren，CHEN Guangjing，KONG Dehao DOI: 10.13228/j.boyuan.issn1006-6543.20230151 This paper mainly introduces the development status, necessity, and significance of high-speed powder forming machine, focuses on the structural composition and product technical characteristics of each part of the high-speed powder forming machine. The High-speed powder forming machine has the advantages of high efficien‐ cy, energy conservation, superior performance, high precision and stability, which can manufacture high-precision, high-density, and high-strength powder product components in an efficient manner. It has a wide range of applica‐ tions and has a trend and requirement towards full intelligence, short process, flexibility, and other directions. 2024 Vol. 34 (02): 134-140 [Abstract] ( 3 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 141 Application and research of powder metallurgy in cam headlock for stand mixer Hot! ZHENG Weiguo，MA Xiaoyuan，LIU Xiaoqing，CHEN Peng DOI: 10.13228/j.boyuan.issn1006-6543.20230019 A powder metallurgy process preparation scheme for the cam head lock of a chef's machine was devel‐ oped and studied. By studying the original design and understanding customer requirements, the structure of the cam head lock forging parts is complex, and it is difficult to ensure the accuracy of key part dimensions, contours, and positions. The low qualification rate of mass production leads to a decrease in quality and an increase in cost. The new scheme utilizes the characteristics of powder metallurgy technology. After the mold is pressed and formed, post-treatment processes such as sintering hardening and tempering are used to ensure size, contour, and part strength. The results show that the quality and efficiency of the parts prepared by the new process scheme have been greatly improved. The subsequent production practice has also verified the economy and practicality of the powder metallurgy process. 2024 Vol. 34 (02): 141- [Abstract] ( 4 ) HTML (1 KB)  PDF  (0 KB)  ( 3 )

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