Home  |  About Journal  |  Editorial Board  |  Instruction  |  Subscribe  |  Advertisement  |  council  |  Contact Us  |  中文

Forthcoming Articles       Current Issue       Advanced Search       Archive       Download Articles       Read Articles       Email Alert

Quick Search     Adv Search   2020 Vol. 30, No. 03 Published: 2020-06-10   1 High performance metal powder development and solutions Hot! TAN Zhao-qiang，Ulf Engstrom，SU Peng-fei，LI Kun，LIU Yong DOI: 10.13228/j.boyuan.issn1006-6543.20190025 The driving force for using PM compared to other manufacturing techniques is almost always due to its ability to produce structural components with close dimensional tolerances and the required performance in a costeffective way. To further grow the PM market into new high challenging automotive applications，cost- effective PM material solutions combining higher precision with increased performance will be required. This can be achieved by different means. The development of new cost-effective alloy systems，new compaction techniques enabling higher densities，sintering at higher temperatures in combination with increased cooling rates，carbon control and adoption of secondary heat treatments，are all examples of ways that either on their own or in combination can be used to increase material performance. The growing awareness of sustainability also makes it important to select both material and manufacturing processes with the least impact on the environment. In this paper some key aspects of the selection of suitable metal powder solutions and the processing conditions needed to meet performance requirements are discussed. These include cost-effectiveness and sustainability for automotive applications like synchronizing hubs，cam lobes，sprockets，gears and other demanding applications that will be presented in this paper. 2020 Vol. 30 (03): 1-8 [Abstract] ( 8 ) HTML (1 KB)  PDF (1934 KB)  ( 4 ) 9 Characteristic of GH4169 alloy powder used in selective laser melting Hot! YANG Qi-yun，XU Jiong-kai，WU Kai-qi，WUWen-heng，ZHANG Liang，HE Bei-bei DOI: 10.13228/j.boyuan.issn1006-6543.20190077 GH4169 alloy powders were prepared by vacuum melting-inert atomization method. The particle size distribution and particle shape characteristics were investigated. GH4169 alloy tensile and metallographic specimens were manufactured by selective laser melting technology. The microstructures and mechanical properties before and after annealing of the specimens were studied. The results show that particle size distribution of GH4169 alloy powder is normal distribution and particle size range is mainly between 25-40 μm. The particles are spherical and there are satellite ball in powders. The average yield strength，tensile strength，elongation and shrinkage before and after annealing of GH4169 alloy specimens are 637 MPa，981 MPa，27.5% and 50.0% respectively. After annealing，the yield strength and tensile strength of the specimen increase while impact energy，elongation and shrinkage reduce. The tensile fracture shows a ductile fracture characteristic. 2020 Vol. 30 (03): 9-13 [Abstract] ( 5 ) HTML (1 KB)  PDF (1895 KB)  ( 6 ) 14 Effects of aging heat treatment on the microstructure and properties of a new type nickel-based PM superalloy Hot! ZHONG Zhi-yong，ZHANG Yi-wen，LIU Jian-tao，JIA Jian，LI Xiao-kun DOI: DOI：10.13228/j.boyuan.issn1006-6543.20190020 The precipitation phases and microstructure of a new type PM superalloy with aging treatments were observed. The tested mechanical properties were listed as follows ：room temperature，750 ℃ and 815 ℃ tensile， 750 ℃/750 MPa stress rupture，and 815 ℃/450 MPa stress rupture. The effects of different aging treatments on the microstructure and properties of the alloy were analyzed. The results show that high secondary aging temperature leads to Ostwald ripening of γ′ phase，which weakens the strengthening effect of γ′ phase，decreases the room temperature and high temperature strength of the alloy ，and shortens the rupture life obviously. The single stage aging results in no further growth of the secondary γ′ phase，and tertiary γ′ phases doesn′t precipitate. The strength of the alloy increases and the plasticity at high temperature decreases significantly. After HT2 heat treatment，the secondary and tertiary γ′ phase match well，the size of γ' phase is appropriate，the strength is slightly decreased， the plasticity is obviously improved，and the comprehensive mechanical properties are excellent 2020 Vol. 30 (03): 14-18 [Abstract] ( 2 ) HTML (1 KB)  PDF (2144 KB)  ( 3 ) 19 Study on preparation and mechanical properties of RGO/Cu composites Hot! LI Mei-xia，FENG Ya-peng，XIE Xiu-liang DOI: 10.13228/j.boyuan.issn1006-6543.20190043 Through the one-step thermal reaction of copper nitrate，thermal glycine and graphene oxide，the RGO/Cu hybrid powder was successfully synthesized，and the RGO/Cu composites were prepared by discharge plasma sintering RGO/Cu hybrid powder. The results show that Cu nanoparticles are uniformly distributed in the RGO lamellae. C-O-Cu covalent bond is formed between RGO and Cu interface in RGO/Cu powder，and it remains in sintered RGO/Cu composites. Compared with pure Cu，the yield strength and tensile strength of 0.6%RGO/Cu composite increase by 75.8% and 47.7% respectively，while maintaining good elongation（29%）. 2020 Vol. 30 (03): 19-24 [Abstract] ( 3 ) HTML (1 KB)  PDF (2273 KB)  ( 4 ) 25 Study on high temperature erosion resistances of protective coatings for heating surface of boiler Hot! LIU Dong-xu DOI: 10.13228/j.boyuan.issn1006-6543.20190047 In order to extend the service life of heating surface tubes of a boiler by increasing its wear resistance， the technology of high velocity arc spraying are utilized to prepare wear-resistant coating of Ni55 on the surface of SA-210C. The spray coating was remelted by a tungsten electrode argon arc welding machine and the microscopic structure，phase composition，bonding strength，microhardness and erosion resistance of the substrate and coating was investigated. The results show that the coating crystal is mainly composed of γ-（Fe，Ni）、Ni3Fe、CrB、 Cr7C3、Cr23C6、Fe3B and WC. The coating forms a typical lamellar structure during deposition，which is mainly dominated by mechanical bond and has good compactness. The bonding strength of spray coating is 40.85 Mpa which is prompted to 53.25 MPa after remelting. The average hardness of the spray coating is 1 081HV which was also prompted to 1 143HV after remelting. In the conditions of erosion angle of 45°，erosion velocity of 200 m/s and temperature of 600 ℃，the remelting coating has the best erosion wear resistance，and the spray coating has better erosion wear resistance than substrate metal. The erosion wear behavior of the remelting coating is same as brittle materials. The hard phases like CrB、Cr7C3、Fe3B are combined strongly with coating，which has the function of resisting continuous cutting by abrasive grains. The erosion mechanism is the peeling of the oxide film and the micro-cutting and ploughing of the substrate metal by the abrasive particles. 2020 Vol. 30 (03): 25-30 [Abstract] ( 4 ) HTML (1 KB)  PDF (1828 KB)  ( 11 ) 31 Microstructure and mechanical properties of double material powder forging connecting rod material Hot! SHAO Jing-jing，MAO Min-jie，LI Jian，ZHANG Guang-wei DOI: ：10.13228/j.boyuan.issn1006-6543.20190063 Due to different working conditions，the main performance requirements of engine connecting rod are different. The powder forging technology can be used to innovatively develop a dual material powder forging connecting rod which can meet the different requirements of connecting big-end and rod.The material is D01（Fe-2.0Cu-0.32MnS-0.6C） at the big-end of the connecting rod，and X01（Fe-3.25Cu-0.6C）is used in the small-end and the rod.The microstructure and mechanical properties of D01，X01 and ZDX（mixed materials of D01 and X01）were studied respectively.The results show that X01 exhibits higher tensile strength and fatigue strength after removing MnS and increasing copper content. The tensile strength and fatigue strength of D01 are slightly weaker，but this material has good plasticity.The two materials can be applied to the connecting rod part and the big-end to better meet the performance requirements of the connecting rod. 2020 Vol. 30 (03): 31-35 [Abstract] ( 2 ) HTML (1 KB)  PDF (1907 KB)  ( 4 ) 36 Experimental study on direct reduction of ultra-pure iron concentrate in a mining company in Qinghai Hot! GAO Shou-kun，CHEN Zheng，YANG Dong-wei， WU Teng DOI: 10.13228/j.boyuan.issn1006-6543.20180177 Abstract：This paper mainly focuses on the ultra-pure iron concentrate with a grade of 71.58% iron obtained by fine grinding，weak magnetic separation，reverse flotation and two-stage dehydration process，with a 68% iron concentrate in marine sedimentary magnetite grade in Qinghai as raw material. The iron ore concentrate can directly produce reduced iron powder with a total iron content of up to 98.7% through the primary reduction of hydrogen.The optimal experimental conditions are as follows：hydrogen flow rate 1.5 m3/h，reduction time 1.5 h，reduction temperature 850 ℃. 2020 Vol. 30 (03): 36-39 [Abstract] ( 2 ) HTML (1 KB)  PDF (1079 KB)  ( 5 ) 40 Analysis of the magnetization status to the magnetic stability of bonded NdFeB magnet Hot! GUO Zhi-wei， XU Hai， XIAO Kai-ye， ZHENGWen DOI: 10.13228/j.boyuan.issn1006-6543.20190093 For bonded NdFeB magnets，the magnetization status not only directly determines the magnitude of the magnetic field provided by the magnet，but also has an important impact on the magnetic stability and material consumption of the magnet. Based on the analysis of flux density variation after saturated magnetization for a certain time，it is found that the magnet with reverse demagnetization after saturated magnetization has better magnetic stability. The larger the range of the reverse demagnetization is，the smaller the loss rate of flux density in air gap caused by external demagnetization field is，and the better the stability of magnetic performance is. And the result of the experiment shows that when the range of the reverse demagnetization is greater than 9%，the magnet has relatively good magnetic stability；and it is verified that the more the material is used，the better the magnetic stability of the magnet is. 2020 Vol. 30 (03): 40-44 [Abstract] ( 2 ) HTML (1 KB)  PDF (1274 KB)  ( 5 ) 45 Microstructure and mechanical properties of AZ31B magnesium alloy reinforced with different graphene content Hot! TANG Duo-chang DOI: 10.13228/j.boyuan.issn1006-6543.20190098 In order to solve the problems of GNPs floating，segregation and poor wettability of metal，powder injection molding was introduced to prepare GNPs reinforced magnesium alloy，and the microstructure and performance of AZ31B magnesium alloy with different GNPs contents were analyzed. The results show that the AZ31B magnesium alloy obtained by powder injection molding has formed a spherical eutectic structure with α-Mg and β- Mg7Al2. With the increases of GNPs，the average grain size decreases from 13.6 μm to 8.2 μm. The diffraction peaks corresponding to Mg and Mg7Al2 are formed on the XRD pattern.When the content of GNPs is increased， the sample density increases and the porosity decreases. The results show that GNPs can inhibit the production of matrix defects. When the content of GNPs increases，the hardness of the sample increases first and then decreases. When the amount of GNPs increases，both the strength and elongation of the sample increases，and the sample with 0.5% GNPs reaches the optimal mechanical properties. 2020 Vol. 30 (03): 45-48 [Abstract] ( 2 ) HTML (1 KB)  PDF (1507 KB)  ( 3 ) 49 Mechanical properties and tissue evolution analysis of Mg-8Zn-2.5Nd-0.8Y magnesium alloys under high strain Hot! HE Yi-ping DOI: 10.13228/j.boyuan.issn1006-6543.20190160 The true stress-true strain curves of the extruded Mg-8Zn-2.5Nd-0.8Y magnesium alloy with different strain rates were measured with separated hopkinson pressure bar，and the structural evolution of the extruded Mg- 8Zn-2.5Nd-0.8Y magnesium alloy with high strain compression was analyzed. The results show that the transverse compression curve has not formed obvious yield，and the deformation is continuous yield. As the strain rate increases， the maximum rheological stress also increases. The longitudinal compression curve has the characteristics of continuous yield and shows obvious positive strain rate enhancement. Both transverse specimen and longitudinal yield strength increase with the increase of strain rate. In the extruded magnesium alloy matrix，an obvious recrystallization structure is formed，and the average size of the grain is about 25 μm. Many twin structures are formed in the matrix after transverse compression of the sample，and these twin crystals usually remain parallel to each other. More fine twin structures are formed after longitudinal compression deformation. 2020 Vol. 30 (03): 49-52 [Abstract] ( 3 ) HTML (1 KB)  PDF (1364 KB)  ( 4 ) 53 Effect of hot rolling temperature on microstructure and mechanical properties of 15%SiC/AZ91B magnesium alloy prepared by powder metallurgy Hot! BAI Hong-wu，YANG Feng DOI: 10.13228/j.boyuan.issn1006-6543.20190143 15%SiC/AZ91B composites was prepared by powder metallurgy. The microstructure and mechanical properties of magnesium alloys at different hot rolling temperatures were tested. The results show that the density of magnesium alloy billet is higher than 99.9% under different hot rolling temperature. When the temperature of hot rolling rises，the density of magnesium alloy increases，and reaches 100% when the temperature is above 550 ℃.Evenly distributed particles are formed in the magnesium alloy at various temperatures，and the COV value increases slightly with the increase of hot rolling temperature and particle size products are formed at the interface. During hot rolling at the temperature of 525-550 ℃，more compounds are formed at the interface and the particle size increases significantly，the maximum size is 30 nm.As the hot rolling temperature rise to 575 ℃，the particle size of the product also increases.When the hot rolling temperature rises from 500 to 550 ℃，the tensile strength decreases while the elongation increases.As the hot rolling temperature rises to 575 ℃，the tensile strength decreases rapidly.After hot rolling at 575 ℃，cracks will be formed near the interface of SiC particles，which weakens the bonding effect of SiC/Mg interface. 2020 Vol. 30 (03): 53-57 [Abstract] ( 3 ) HTML (1 KB)  PDF (2016 KB)  ( 4 ) 58 Effect of sintering process on microstructure and properties of medical Ti-Nb-Ta- Zr alloy Hot! LI Bo-qiong，XIE Rui-zhen，LI Chun-lin DOI: 10.13228/j.boyuan.issn1006-6543.20200035 β titanium alloy with low modulus has become a research hotspot in biomedical implant materials because of its excellent biocompatibility. Ti-Nb-Ta- Zr alloy with non- toxic alloying elements has been developed widely for biomaterials due to its high strength and significant plasticity. In this paper，Ti-35Nb-7Zr-5Ta alloy was prepared by traditional powder metallurgy method in order to further regulate the uniformity. Based on the distribution of microhardness，the uniformity of phase distribution was analyzed according to the uniformity index and hardness variation coefficient. The effect of sintering process on the microstructure and mechanical properties of Ti- 35Nb-7Zr-5Ta alloy was studied. The experimental results show that with the increase of sintering temperature and holding time，the pore size of the matrix decreases gradually or even disappears，resulting in the phase compositions and distribution changing accordingly. The Young's modulus of Ti-35Nb-7Zr-5Ta alloy increases firstly and then decreases within（4.77±0.48）-（7.4±0.81）GPa，which is close to that of cancellous bone. In the simulated body fluid environment，the impedance spectrum of the sintered Ti-35Nb-7Zr-5Ta alloy exhibits a semi-capacitive arc-resistance characteristic，and the phase angle has a peak value in the wide frequency domain of 10－1-102 Hz. It indicates that the sintered Ti-35Nb-7Zr-5Ta alloy has high corrosion resistance and provides a theoretical basis for the study of biomechanical properties of medical titanium alloys. 2020 Vol. 30 (03): 58-63 [Abstract] ( 4 ) HTML (1 KB)  PDF (1862 KB)  ( 5 ) 64 Microstructure and properties analysis of porous stainless steel for building by powder metallurgy Hot! NIU Ping-ping，LIU Ying，CAO Ping DOI: 10.13228/j.boyuan.issn1006-6543.20190123 The porous stainless steel materials for construction were prepared by powder metallurgy process. The mechanical strength and corrosion resistance with different porosity were tested.The results show that when the amount of pore-forming agent increases，more pores are formed and the porosity increases，resulting in more uniform pores.Each sample contains austenite A phase and partial nitride，precipitates a certain amount of CrN and Cr2N.When the content of pore-forming agent increases，the tensile strength and yield strength of the sample decreases slowly，and there are significant differences in mechanical properties between the porous block and the block with dense structure.When the addition of pore-forming agent increases，the self-corrosion potential of the sample decreases gradually，from －0.761 V to －0.988 V. The corrosion rate increases with corrosion current density increasing from 0.002 mA/cm2 to 0.496 mA/cm2. 2020 Vol. 30 (03): 64-67 [Abstract] ( 5 ) HTML (1 KB)  PDF (1464 KB)  ( 4 ) 68 Characterization of ZrB2＋SiC composite powder coating on C/C composite surface for building Hot! TANG Xu-lin DOI: 10.13228/j.boyuan.issn1006-6543.20190091 Induced plasma spherification（IPS）method was used to prepare ZrB2＋SiC composite coatings on the surface of C/C composite materials used in construction. The effects of SiC particle content on the microstructure and properties of the coatings were studied.The results show that the main phases ZrB2 and ZrSi2 are contained in the coating，and some Si are present too.The composite ceramic structure is formed in the coating product，which is mainly composed of gray particles with higher SiC content and white particles with higher ZrB2 content.After IPS treatment，SiC is decomposed into vapors of C and Si，the surface layer of the powder has a higher temperature than the core，which leads to faster decomposition of the surface SiC.The gray and white particles are aggregated， and a large number of pore structures are formed in the matrix of the products，different particles form a tight bonding state.Spherical and ellipsoidal particles with particle size less than 20 μm are obtained by IPS treatment. 2020 Vol. 30 (03): 68-72 [Abstract] ( 6 ) HTML (1 KB)  PDF (1790 KB)  ( 3 ) 73 Applications of surface forming technology in PM machine part development Hot! BAO Si-ping，CHEN Fang DOI: 10.13228/j.boyuan.issn1006-6543.20200056 Surface Forming Technology（SFT）and its technical characteristics are introduced in this paper，based on the practices of PM machine part development. SFT follows the general limits of press molding technology. SFT is a kind of combined application with both geometric and nongeometric elements to define the surface and/or define the tooling surface which formed PM machine part directly. The geometric elements include dot，line， face，and so on. The nongeometric elements mean word，pattern，texture，roughness，etc. The purpose of the applications above is to meet the requirements of the product structure and function design，process development and/ or process management. In this paper，a series of typical application examples are presented to demonstrate the application scenarios and application techniques of SFT，and to provide guidelines for SFT applied in PM machine part development. 2020 Vol. 30 (03): 73-78 [Abstract] ( 4 ) HTML (1 KB)  PDF (1549 KB)  ( 7 ) 79 The performance characteristics of "foam aluminum" and its application in automobile industry Hot! ZHANG Hong-ying，OU YANG Ba-sheng DOI: 10.13228/j.boyuan.issn1006-6543.20190175 Foam metal is a new type of structural functional material composed of metal matrix and a large number of channels. It has excellent properties such as heat，sound，light and energy absorbing.Porous aluminum foam is the most popular and most promising foam metal at present. As a "metal star"，aluminum foam has many excellent properties such as small density，high temperature resistance，corrosion resistance，non-flammability，good weather resistance，low thermal conductivity，strong electromagnetic shielding，energy absorption and noise reduction，and is widely used in automotive industry，aerospace and construction industry and other engineering fields. The structural characteristics，application properties and application progress of aluminum foam in engineering are summarized in this paper. 2020 Vol. 30 (03): 79-82 [Abstract] ( 3 ) HTML (1 KB)  PDF (1001 KB)  ( 4 ) 83 Research progress in the application of copper oxide nanomaterials in sensors Hot! HAO Gui-min，SHI Jun-tao，WANG Xin，ZHANG Guang-chao DOI: 10.13228/j.boyuan.issn1006-6543.20190186 Due to their superior physical or chemical properties，nanomaterials have developed rapidly in recent years and have played a huge role in various industries. Copper oxide is the most common oxide. Copper oxide nanomaterials with various structural morphologies，such as copper oxide nanowires，nanosheets，nanorods， nanotubes，nanoflowers，etc.，have been prepared by various methods. Nanomaterials greatly improve the analytical performance of electrochemical sensors and make a significant contribution to the ultrasensitive detection of a wide range of materials. In this paper，the application of copper oxide nanomaterials in electrochemical sensors has been summarized in recent years，and the future development trend of this material in sensors is prospected. 2020 Vol. 30 (03): 83-86 [Abstract] ( 3 ) HTML (1 KB)  PDF (905 KB)  ( 4 ) 87 Type selection and structure design of feeding mechanism for tungsten and molybdenum powder automatic screening platform Hot! CHEN Hai-feng，GUO Jian-wei，SUWei-feng DOI: 10.13228/j.boyuan.issn1006-6543.20190116 In light of the low level of automation of the current screening equipment commonly used in the tungsten and molybdenum industry，a fully automatic screening platform fitted with a screw feeder has been designed by means of model selection，and its parameter design takes into account the characteristics of tungsten powder and molybdenum powder，realizes the stepless adjustment of the screening speed and the automatic screening of tungsten powder and molybdenum powder，reduces the labor intensity of workers，improves the production efficiency， and decreases the damage of dust to the environment and workers. 2020 Vol. 30 (03): 87-90 [Abstract] ( 4 ) HTML (1 KB)  PDF (1204 KB)  ( 5 )

Copyright © Editorial Board of Powder Metallurgy Industry Supported by:Beijing Magtech