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Quick Search     Adv Search   2020 Vol. 30, No. 06 Published: 2020-12-10   1 Progress in preparation and modification of nano zero valent iron Hot! LI Chengwei，LIU Qian，LIU Shuai，LIU Hongwei DOI: 10.13228/j.boyuan.issn1006-6543.20200230 Nano zero-valent iron（nZVI）has the characteristics of small particle size，large specific surface area， and strong reducibility. It has good adsorption and reduction effects on heavy metals and organic pollutants，and shows good environmental remediation capabilities. However，nZVI has the problem of easy oxidation and agglomeration when using it，which limits its application. This article briefly introduces several commonly used preparation methods and modification methods of nZVI，and looks forward to the future research directions of nZVI. 2020 Vol. 30 (06): 1-7 [Abstract] ( 17 ) HTML (1 KB)  PDF (1836 KB)  ( 6 ) 8 Research of parameters on the effect of CoCr alloys pherical powders produced by RF plasma Hot! LU Chao，XIAO Mengzhi，QU Yuebo，WEI Xiaohong，LIU Ruijun， ZHANG Ruihua DOI: 10.13228/j.boyuan.issn1006-6543.20190075 In this paper，the plasma spheroidization technology was used for the surface-treatment of cobalt-chromium alloy powders which were used in selective laser melting additive manufacturing process. The results show that powders with good sphericity and surface morphology can be obtained under the optimized spheroidization process parameters.There is little change of the microstructure before and after spheroidization，mainly cellular crystal，and the dendritic structure increases with the increases of powder particle size. Laser particle size analyzer shows that the particle size of cobalt-chromium alloy powder increases after plasma spheroidization，mainly due to the evaporation of fine powders.This experiment is helpful to solve the recycling problem of selective laser melting powder materials. 2020 Vol. 30 (06): 8-14 [Abstract] ( 14 ) HTML (1 KB)  PDF (2909 KB)  ( 5 ) 15 Dynamic simulation of sintering neck growth with coupling multiple physical field Hot! TAN Shulin，ZHANG Xiaomin，ZHAO Zhipeng，WU Zhouzhi DOI: 10.13228/j.boyuan.issn1006-6543.20190180 A fully coupled thermo-mechano-diffusional phase field model was presented to investigate the relationship between the driving force and the neck growth during solid sintering. It could be seen from the morphological evolution that the neck radius will increases gradually and the neck curvature decreases with the interface migration in the sintering process. Moreover，with the decreasing of total surface area of the system，and the pores become circular and reduce gradually. The simulation results show that the strain gradient coupling term play a domain role in the fully-coupled condition，and the effect of the temperature gradient coupling term is negligible. Finally， dynamic equations can be obtained by contrastive analysis among the change of neck growth rates and driving forces of neck growth. It indicateds that the neck growth rate is the product of the neck growth driving forces to the power of k0 and the physical parameters CM which relates to the diffusion mobility. And the neck growth driving forces is only related to the shape of neck，and has nothing to do with sintering speed and sintering process. 2020 Vol. 30 (06): 15-20 [Abstract] ( 8 ) HTML (1 KB)  PDF (1791 KB)  ( 9 ) 21 Effect and optimization of process variables on preparation of copper coated iron powder by mechanochemistry Hot! LI Shiwen，PANG Jianming，FANG Jianfeng，PAN Congchao，SONG Yaoxin DOI: 10.13228/j.boyuan.issn1006-6543.20190142 By the orthogonal design of 4 factors and 3 levels，taking the coating rate of copper coated iron powder （CCIP）as an index，the influence of process variables on preparation of（CCIP）by mechanochemistry was analyzed， the priority of factors were determined and the superior combined level was selected. The results show that the sequence of factors is：mixing time、sintering time、batching ratio、reduction temperature，and the optimal level combination is the ratio of iron powder to copper oxide powder is 4：1，the high-speed mixing time is 20 min，the sintering temperature is 900 ℃，the sintering time is 3 h. At this time，the coating rate of copper coating layer can reach 95%. The analysis indicats that copper coated rate increases first but then drops with the increase of mixing time. The reason is that over a certain mixing time，some CuO particles on the Fe-CuO composite particles are peeled off under the strong mechanical force and the activity of bare surface of Fe particles decreases due to oxidation or adsorption of tiny fine particles，which make readsorption of CuO particles difficult. Thus，the coating rate is reduced. At the same time，the increase of sintering time can reduce the porosity as well as densification of the copper coated layer，and improve the coating rate. 2020 Vol. 30 (06): 21-27 [Abstract] ( 7 ) HTML (1 KB)  PDF (2569 KB)  ( 6 ) 28 Development of powder metallurgy eccentric gear Hot! YANG Chuanfang， WANG Shiping， DU Jing DOI: 10.13228/j.boyuan.issn1006-6543.20190202 Aiming at the structural characteristics and operating conditions of eccentric large gear，the strength parameters of gear are determined，the matching state of die is simulated by three-dimensional software，the design parameters of die are optimized，and the appropriate raw materials，sintering and heat treatment process are selected through metallographic analysis，and the finished product is manufactured after proper post-processing. 2020 Vol. 30 (06): 28-33 [Abstract] ( 5 ) HTML (1 KB)  PDF (2053 KB)  ( 5 ) 34 Fracture failure analysis on tungsten infiltrated copper stud Hot! ZHANG Baohong， TAN Zhi， LIN Bingtao， GAO Zhuqing， TANG Liangliang， SUN Xiaoxia DOI: 10.13228/j.boyuan.issn1006-6543.20200141 Taking tungsten infiltrated copper (W10Cu) studs used in aircraft as the research object, the fracture phenomenon of loading moment in the assembly process of products was analyzed. The results show that uneven copper infiltration is the main reason for stud fracture caused by the decrease of material strength, and the methods and suggestions for optimizing material sintering process and quality monitoring are put forward. 2020 Vol. 30 (06): 34-38 [Abstract] ( 7 ) HTML (1 KB)  PDF (2338 KB)  ( 4 ) 39 Microstructure and properties of selective laser melting formed H13 die steel and tempered treatment Hot! CHENWeidong，HUANG Jiahao，WEN Liping，CHEN Jin，XIAO Zhiyu DOI: 10.13228/j.boyuan.issn1006-6543.20190237 In order to improve mechanical properties，the effect of tempered treatment at different holding temperature ranges from 450 to 700 ℃ on the microstructure and mechanical properties of H13 steel fabricated by selective laser melting（SLM）were investigated. The microstructural study of the H13 steel by SLM shows both martensite and austenite phases are existing. With the increasing of tempered temperature，retained austenite and martensite in the matrix are completely transformed to tempered martensite. The tiny alloy carbide has been gradually precipitated and grew from matrix. Hardness and tensile tests demonstrate that the hardness and ultimate tensile strength（UTS）values first increase and then decrease steadily when the holding temperature increases from 450 to 700 ℃. The distinct fracture surface of tensile specimens is changed from tear ridges to dimples. Compared with asbuilt sample，the microhardness of tempered treatment sample at 550 ℃ is improved from 579.8HV0.5 to 714HV0.5；the UTS of tempered treatment sample at 600 ℃ reaches 1 958 MPa from 1 479 MPa；the elongation of tempered treatment sample at 700 ℃ is increased from 4.5% to 11.2%. 2020 Vol. 30 (06): 39-44 [Abstract] ( 4 ) HTML (1 KB)  PDF (2727 KB)  ( 5 ) 45 Effects of Ti content on microstructure and mechanical properties of Mo-Ti alloys Hot! NIU Xuanyang，ZHANG Pengfei，WANG Guangxin DOI: 10.13228/j.boyuan.issn1006-6543.20190209 Five kinds of Mo-Ti alloys with different composition were prepared with high purity titanium powder and molybdenum powder by hot pressing at 1 600 ℃ and 40 MPa for 3 h under the protection of Argon. Effects of titanium content on mechanical property and microstructure of the prepared Mo-Ti alloys were studied. Results obtained show that Mo and Ti atoms can form displacement solid solution，and Mo-Ti alloy is brittle at room temperature. With titanium content increasing from 10 atm.% to 50 atm.% ，grain size increases from about 7 μm to 15 μm，relative density increases from 95.8% to 99.5%，rockwell hardness increases from 22.3 HRC to 45.5 HRC， and bending strength increases from 396 MPa to 680 MPa. Mo-50% Ti has the best performance in all aspects， which has a certain significance for the preparation of Mo-Ti alloy target and the study of sputtering performance. 2020 Vol. 30 (06): 45-49 [Abstract] ( 4 ) HTML (1 KB)  PDF (2181 KB)  ( 4 ) 50 Preparation and properties of copper-based carbon fiber brake pads friction materials Hot! SHI Yongliang，HUANGWeiqing，CHEN Cunguang，SHI Yanlin DOI: 10.13228/j.boyuan.issn1006-6543.20190162 Copper-based carbon fiber brake pads were prepared by cold pressing sintering with dispersed copper as matrix and copper-plated carbon fiber as reinforcing lubricant phase. The microstructure，tensile fracture and wear morphology of copper- based brake pads were observed by scanning electron microscopy. The hardness，tensile strength，friction coefficient and wear amount were tested and analyzed. The results show that the carbon fibers are evenly distributed in the matrix and well bonded with the matrix. The addition of carbon fibers can improve the hardness and tensile strength，reduce friction coefficient and improve the wear resistance of the materials. The optimum carbon fibers mass fraction is 0.5%-0.7%. 2020 Vol. 30 (06): 50-54 [Abstract] ( 4 ) HTML (1 KB)  PDF (2530 KB)  ( 3 ) 55 Effect of rare earth on microstructure and properties of PCBN composites synthesized Hot! LUO Tao，JIANGWenqing，WU Jinhui，LIU Xiaohong DOI: 10.13228/j.boyuan.issn1006-6543.20200127 PCBN composites were prepared by sintering rare earth Eu2O3 and Pr2O3 as additives in the cBN-Al-Ti system at high temperature（1600 ℃）and high pressure（5.5 GPa）. The effects of rare earth on the phase，microstructure， porosity and mechanical properties of PcBN were studied. The results show that the addition of Eu2O3 and Pr2O3 not only improves the morphology of the reinforced phase TiB2 and reduces the porosity of the sample，but also increases the hardness and bending strength of the sintered body. When adding rare earth Pr2O3，PCBN obtains the best mechanical properties，its microhardness reaches 40.15 GPa，and its bending strength reaches 801.24 MPa. 2020 Vol. 30 (06): 55-59 [Abstract] ( 3 ) HTML (1 KB)  PDF (1668 KB)  ( 3 ) 60 Research on preparation and characteristic of water wall tube nickel-based coating Hot! SUN Yue，NING Yuheng，WANG Ao DOI: 10.13228/j.boyuan.issn1006-6543.20190215 The working environment of the water wall tube is poor，which has to be subjected to high temperature， high pressure and gas corrosion. Therefore，the thickness of water wall tube is decreased or even causing the explosion accident. Ni-based wear-resisting coating（Ni60 cladding layer）is prepared by laser cladding technology in this paper. The microstructure of the coating was analyzed，and the microhardness，wear resistance and corrosion resistance of the coating and the substrate were compared and tested. The results show that the microstructure of coating is uniform due to the rapid cooling rate of laser processing，microstructure mainly contains dendritic primary Ni grains and eutectics. Microhardness of Ni60 cladding layer is 2.5 times harder as compared to the matrix. The wear loss weight of matrix is 2 times as compared to Ni60 cladding layer at high temperature. And the cladding coating has good resistance of corrosion. 2020 Vol. 30 (06): 60-64 [Abstract] ( 3 ) HTML (1 KB)  PDF (1877 KB)  ( 4 ) 65 Effect of sputtering power on the properties of Zr51Al11Ni4Cu34 amorphous alloy films for medical device by DC magnetron sputtering Hot! GE Hongyang，WANG Yongle DOI: 10.13228/j.boyuan.issn1006-6543.20200058 The amorphous alloy films using Zr51Al11Ni4Cu34 alloy as single target were prepared on glass substrate by DC magnetron sputtering，and the effects of sputtering power on microstructure，mechanical property and electrical property were analyzed by XRD，SEM，nano- indentation tester and four point probe tester. The results show that all the films are amorphous and gain the highest degree of amorphization at 100W，and there are still obvious cracks at 200 W. The hardness and elastic modulus of films are not obviously changed with the increasing of sputtering power，the hardness is 459-510HV and the elastic modulus is 90-94 GPa. The resistivity of films decreases from 7.05×10－3 to 1.09×10－3 Ω·cm with the increasing of sputtering power. 2020 Vol. 30 (06): 65-68 [Abstract] ( 3 ) HTML (1 KB)  PDF (1843 KB)  ( 4 ) 69 Analysis of microstructure and mechanical properties of siliceous rock /5052 composites for construction by jet forming Hot! JIANG Huaguo，LI Ming DOI: 10.13228/j.boyuan.issn1006-6543.20200021 Siliceous rock particles were used as the reinforcing body，and the siliceous rock/aluminum-based composite material was prepared by jet forming process. The results show that a large number of dispersed siliceous rock particles are produced in the aluminum matrix，and the particles of different particle sizes can be captured efficiently to achieve uniform distribution. The siliceous rock particles are in a good Mosaic state with the aluminum matrix，and a large number of dislocations occur close to the interface，and obvious dislocations occur at the interface between the matrix and the particles. The content of Si at the transition zone is small and Al is obviously increased. When the siliceous rock particles are added into the alloy，the mechanical properties of the aluminum-matrix composites are significantly improved，and the tensile strength and elongation are significantly increased，the increase proportion is more than 10%. The fracture morphology of the alloy is characterized by ductile fracture， with flat structure and a large number of dimples. 2020 Vol. 30 (06): 69-73 [Abstract] ( 1 ) HTML (1 KB)  PDF (1896 KB)  ( 4 ) 74 Comparative study on properties of ultrafine cemented carbide raw materials Hot! ZHU Ertao，ZHANG Jiuxing，YANG Xinyu，PAN Yafei，YANG Jiangao DOI: 10.13228/j.boyuan.issn1006-6543.20190210 Using XRD，SEM，ICP and Laser Particle Size Meter to compare the phase，grain size，composition and particle size of WC and WC-6Co composite powder，the results show that：the phase purity，grain size uniformity and impurity element content are different，the WC-6Co composite powder grain size is 0.2 μm. While compare the production process，producing method and properties，the results show that：WC-6Co composite powder has shorter production process，more simple equipment and more homogenous element distribution. WC-6Co composite powder has higher hardness and less strength than the WC and Co powder mixture. 2020 Vol. 30 (06): 74-79 [Abstract] ( 4 ) HTML (1 KB)  PDF (2003 KB)  ( 7 ) 80 Research progress on HIP diffusion bonding of molybdenum alloys Hot! WANG Tiejun，ZHANG Longge，CHE Hongyan，DU Yaxiong，LI Lin DOI: 10.13228/j.boyuan.issn1006-6543.20190119 In this paper，the mechanism of diffusion bonding and the process characteristics of HIP are briefly analyzed. The application of diffusion bonding technology in molybdenum alloys is introduced from the aspects of the selection of intermediate layer system and process parameters. Finally，the currently process progress is summarized and the future development trend is prospected. 2020 Vol. 30 (06): 80-84 [Abstract] ( 3 ) HTML (1 KB)  PDF (1940 KB)  ( 3 ) 85 Influencing factors of performance of aluminium-based oil bearing Hot! WU Kaixia，WEN Ran，WANG Zhu，WANG Zi，JING Zhijie DOI: 10.13228/j.boyuan.issn1006-6543.20190128 Aluminium based oil-impregnated bearing has been extensively studied because of its light products and better running-in ability，etc. Crushing strength and oil content are two important indexes for evaluating the performance of oil bearing，which are influenced by many factors. In this paper，the effects of alloy elements，ball milling process and sintering process on crushing strength and oil content of aluminium- based oil bearing are discussed， and the future research and development are prospected. 2020 Vol. 30 (06): 85-88 [Abstract] ( 2 ) HTML (1 KB)  PDF (1087 KB)  ( 5 ) 89 The production process and microstructure of Nickel-based powder metallurgy（PM）superalloy FGH4097 Hot! XU Ming，HOU Qiong，LI Chang，YANG Sheng，LIU Jiantao，QU Jinglong DOI: 10.13228/j.boyuan.issn1006-6543.20200232 The research work on the composition design，production process and microstructure of high alloying γ′ phase precipitation enhanced Nickel-based powder metallurgy（PM）superalloy FGH4097 developed in China in the early 21st century were summarized in this paper. The further investigation in improving the material utilization of FGH4097 turbine disk was discussed. 2020 Vol. 30 (06): 89-95 [Abstract] ( 5 ) HTML (1 KB)  PDF (3162 KB)  ( 6 ) 96 Process improvement of saw tooth limitation of grinding integral carbide tool in five axis tool grinding machine Hot! JIANG Xiangyan，LIU Aiqiang，XIE Peng DOI: 10.13228/j.boyuan.issn1006-6543.20200081 In order to solve the problem of saw tooth limitation out of tolerance in the grinding process of solid carbide tools，the experiments were carried out from the angle of grinding wheel size，feed speed，process sequence and tool path density. The results show that a lower grinding wheel size，a lower feed speed within a certain range， a reasonable sequence of work steps，and a higher tool path density can effectively improve the saw tooth limit out of tolerance and obtain a good overall quality of cemented carbide cutting edge. 2020 Vol. 30 (06): 96-101 [Abstract] ( 2 ) HTML (1 KB)  PDF (2651 KB)  ( 5 ) 102 Recent development of new type powder metallurgy superalloys in Russia Hot! ZHANG Yiwen，JIA Jian，LIU Jiantao，QU Jinglong DOI: 10.13228/j.boyuan.issn1006-6543.20200193 This article reviews the research progress of powder metallurgy（PM）superalloys in Russia from 2015 to 2019. The microstructure and mechanical properties of ВВП nickel base PM superalloys are overviewed，such as ВВ750П，ВВ751П，ВВ752П and ВВ753П，which are developed by Russian Institute of Light Alloy（ВИЛС）. It is also reviewed the microstructure and mechanical properties of a new kind of PM superalloy named ВЖ178П， which is developed by Russian Institute of Aeronautical Materials（ВИАМ）. ВИЛС prepared disk billet by plasma rotating electrode process（PREP）and as-hot isostatic pressing（as-HIP）. Since October 2014，ВВ751П alloy powder with particle size of no more than 70μm has been used by ВИЛС to produce disk for ПД14 engine. ВИАМ adopts argon atomization（AA）and PREP to prepare alloy powders. The particle size distribution，gas content in powders，preparation technology，microstructure characteristics，microstructure and process plasticity of HIP billet， and microstructure and mechanical properties of forgin ingot were compared between AA powders and PREP powders. ВИАМ developed the disk billet（320 mm in diameter）of ВЖ178П alloy by HIP and isothermal forging process，and the mechanical properties of this alloy were better than those of the same kind in Russia and abroad. Compared with AA powders，PREP powders ensure that the deformed disk has higher mechanical properties at room temperature. Using PREP ВЖ178П powders and as-HIP process，full-scale experimental disk billet（600 mm in diameter）was first developed，and its mechanical properties met the modern requirements of areo-engine disk materials. 2020 Vol. 30 (06): 102-116 [Abstract] ( 5 ) HTML (1 KB)  PDF (4398 KB)  ( 6 )

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