Metal matrix composites tiles based on Ti-6Al-4V(Ti64)alloy,reinforced with 10,20,and 40(vol%)of either TiC or TiB particles were made using press-and-sinter blended elemental powder metallurgy(BEPM)and then bonded to...Metal matrix composites tiles based on Ti-6Al-4V(Ti64)alloy,reinforced with 10,20,and 40(vol%)of either TiC or TiB particles were made using press-and-sinter blended elemental powder metallurgy(BEPM)and then bonded together into 3-layer laminated plates using hot isostatic pressing(HIP).The laminates were ballistically tested and demonstrated superior performance.The microstructure and properties of the laminates were analyzed to determine the effect of the BEPM and HIP processing on the ballistic properties of the layered plates.The effect of porosity in sintered composites on further diffusion bonding of the plates during HIP is analyzed to understand the bonding features at the interfaces between different adjacent layers in the laminate.Exceptional ballistic performance of fabricated structures was explained by a significant reduction in the residual porosity of the BEPM products by their additional processing using HIP,which provides an unprecedented increase in the hardness of the layered composites.It is argued that the combination of the used two technologies,BEPM and HIP is principally complimentary for the materials in question with the abilities to solve the essential problems of each used individually.展开更多
Titanium has found extensive use in various engineering applications due to its attractive physical,mechanical, and chemical characteristics. However, titanium has relatively low hardness for use as an armour material...Titanium has found extensive use in various engineering applications due to its attractive physical,mechanical, and chemical characteristics. However, titanium has relatively low hardness for use as an armour material. ZrB2 was incorporated to the Ti matrix to form a Ti-based binary composites. In this study, powder metallurgy techniques were employed to disperse the ceramic particulates throughout the matrix material then consolidated through spark plasma sintering. The composites were densified at1300 ℃, pressure of 50 MPa, and holding time of 5 min. The microstructure and phase analysis of the sintered composites was carried out using SEM and XRD, while the hardness was determined using Vickers' microhardness tester. The SEM and XRD results confirmed the presence of the TiB whiskers which renowned with the improving the hardness of titanium. The hardness of the composite with 10 wt% ZrB_2 showed the highest hardness compared to that obtained for the 5 and 15 wt% ZrB_2 composites which was 495 and 571 Hv respectively.展开更多
Resin matrix carbon brush composites(RMCBCs)are critical materials for high-powered electric tools.However,effectively improving their wear resistance and heat dissipation remains a challenge.RMCBCs prepared with flak...Resin matrix carbon brush composites(RMCBCs)are critical materials for high-powered electric tools.However,effectively improving their wear resistance and heat dissipation remains a challenge.RMCBCs prepared with flake graphite powders that were evenly loaded with tungsten copper composite powder(RMCBCs-W@Cu)exhibited a low wear rate of 1.63 mm^(3)/h,exhibiting 48.6%reduction in the wear rate relative to RCMBCs without additives(RMCBCs-0).In addition,RMCBCs-W@Cu achieved a low friction coefficient of 0.243 and low electric spark grade.These findings indicate that tungsten copper composite powders provide particle reinforcement and generate a gradation effect for the epoxy resin(i.e.,connecting phase)in RMCBCs,which weakens the wear of RMCBCs caused by fatigue under a cyclic current-carrying wear.展开更多
In the present manuscript numerical analysis on the ballistic performance of a tungsten particle/metallic glass matrix(WP/MG) composite rod is conducted by integrating with related experimental investigations. In the ...In the present manuscript numerical analysis on the ballistic performance of a tungsten particle/metallic glass matrix(WP/MG) composite rod is conducted by integrating with related experimental investigations. In the corresponding finite element method(FEM) simulations a modified coupled thermomechanical constitutive model is employed to describe the mechanical properties of metallic glass(MG)matrix, and geometrical models of the WP/MG composite rod are established based on its inner structure. The deformation and failure characteristics of the rod and target materials are analyzed in detail,and the influences of various factors on the ballistic performance of the WP/MG composite long rod are discussed. Related analysis demonstrates that the penetrating performance of the WP/MG rod is similar to that of the tungsten fiber/metallic glass matrix(WF/MG) composite long rod, i.e., a "self-sharpening" behavior also occurs during the penetration process, and correspondingly its penetrating capability is better than that of the tungsten heavy alloy(WHA) rod. However, the mass erosion manner of the WP/MG rod is different and the erosion is relatively severe, thus its penetrating capability is a little lower compared with that of the WF/MG one. Moreover, the impact velocity and the target strength have significant influences on the ballistic performance of the WP/MG composite rod, whereas the effect of initial nose shape is very little.展开更多
In this study,a mathematical model was developed to optimize the heat treatment process for maximum tensile strength and ductility of aluminum(8011) silicon carbide particulate composites.The process parameters are so...In this study,a mathematical model was developed to optimize the heat treatment process for maximum tensile strength and ductility of aluminum(8011) silicon carbide particulate composites.The process parameters are solutionizing time,aging temperature,and aging time.The experiments were performed on an universal testing machine according to centre rotatable design matrix.A mathematical model was developed with the main and interactive effects of the parameters considered.The analysis of variance technique was used to check the adequacy of the developed model.The optimum parameters were obtained for maximum tensile strength.Fractographic examination shows the cracks and dimples on the fractured surfaces of heat-treated specimen.展开更多
Titanium metal matrix composite(Ti-MMC)has excellent features and capabilities which can be considered a potential candidate to replace commercial titanium and superalloys within an extensive range of products and ind...Titanium metal matrix composite(Ti-MMC)has excellent features and capabilities which can be considered a potential candidate to replace commercial titanium and superalloys within an extensive range of products and industrial sectors.Regardless of the superior features in Ti-MMC,however,referring to several factors including high unit cost and existence of rigid and abrasive ceramic particles in the generated matrices of the work part,the Ti-MMC is grouped as extremely difficult to cut with a poor level of machinability.Furthermore,adequate process parameters for machining Ti-MMCs under several lubrication methods are rarely studied.Therefore,adequate knowledge of this regard is strongly demanded.Among machinability attributes,ultrafine particles(UFPs)and fine particles(FPs)have been selected as the main machinability attributes and the factors leading to minimized emission have been studied.According to experimental observations,despite the type of coating used,the use of higher levels of flow rate led to less UFPs,while no significant effects were observed on UFPs.Under similar cutting conditions,higher levels of FPs were recorded under the use of uncoated inserts.Moreover,cutting speed had no significant influence on UFPs;nevertheless,it significantly affects the FPs despite the type of insert used.展开更多
电子信息系统小型化、轻量化、无人化、一体化的发展趋势要求电子封装持续减小尺寸、降低重量和减少功耗(SWaP,即Size,Weight and Power)。传统的基于可伐合金、铝合金和高硅铝的微电子封装材料难以同时满足大跨度热匹配、良好的钎焊与...电子信息系统小型化、轻量化、无人化、一体化的发展趋势要求电子封装持续减小尺寸、降低重量和减少功耗(SWaP,即Size,Weight and Power)。传统的基于可伐合金、铝合金和高硅铝的微电子封装材料难以同时满足大跨度热匹配、良好的钎焊与激光熔焊性能、高导热、高比刚度、高比强度和良好的可制造性,无法适应SWaP要求。功能梯度铝基复合材料综合了铝合金与铝硅、碳化硅铝等先进复合材料的优点,既具备大跨度热匹配、高导热率的特点,又具备精细加工和良好的激光熔焊等工艺性能,是新一代微电子封装材料的研究热点。本文综述了功能梯度铝基复合材料的优势、制备方法和封装应用情况,并对该材料制备与应用中存在的问题进行了总结,最后对其未来研究方向进行了展望。展开更多
基金funding from the NATO Agency Science for Peace and Security (#G5787)Ballistic investigations were co-financed by Military University of Technology in Warsaw under research project UGB 829/2023/WATSeparate works made in G.V.Kurdyumov Institute for Metal Physics of N.A.S.of Ukraine were partially financially supported by N.A.S.of Ukraine within the frames of project#III09-18。
文摘Metal matrix composites tiles based on Ti-6Al-4V(Ti64)alloy,reinforced with 10,20,and 40(vol%)of either TiC or TiB particles were made using press-and-sinter blended elemental powder metallurgy(BEPM)and then bonded together into 3-layer laminated plates using hot isostatic pressing(HIP).The laminates were ballistically tested and demonstrated superior performance.The microstructure and properties of the laminates were analyzed to determine the effect of the BEPM and HIP processing on the ballistic properties of the layered plates.The effect of porosity in sintered composites on further diffusion bonding of the plates during HIP is analyzed to understand the bonding features at the interfaces between different adjacent layers in the laminate.Exceptional ballistic performance of fabricated structures was explained by a significant reduction in the residual porosity of the BEPM products by their additional processing using HIP,which provides an unprecedented increase in the hardness of the layered composites.It is argued that the combination of the used two technologies,BEPM and HIP is principally complimentary for the materials in question with the abilities to solve the essential problems of each used individually.
基金supported financially by the National Research Foundationthe support from the the Tshwane University of Technology, Pretoria, South Africa which helped to accomplish this work
文摘Titanium has found extensive use in various engineering applications due to its attractive physical,mechanical, and chemical characteristics. However, titanium has relatively low hardness for use as an armour material. ZrB2 was incorporated to the Ti matrix to form a Ti-based binary composites. In this study, powder metallurgy techniques were employed to disperse the ceramic particulates throughout the matrix material then consolidated through spark plasma sintering. The composites were densified at1300 ℃, pressure of 50 MPa, and holding time of 5 min. The microstructure and phase analysis of the sintered composites was carried out using SEM and XRD, while the hardness was determined using Vickers' microhardness tester. The SEM and XRD results confirmed the presence of the TiB whiskers which renowned with the improving the hardness of titanium. The hardness of the composite with 10 wt% ZrB_2 showed the highest hardness compared to that obtained for the 5 and 15 wt% ZrB_2 composites which was 495 and 571 Hv respectively.
基金Projects(51772081,51837009,51971091)supported by the National Natural Science Foundation of ChinaProject(HFZL2018CXY003-4)supported by the Industry-University-Research Cooperation of AECC,ChinaProject(kq1902046)supported by the Major Science and Technology Projects of Changsha City,China。
文摘Resin matrix carbon brush composites(RMCBCs)are critical materials for high-powered electric tools.However,effectively improving their wear resistance and heat dissipation remains a challenge.RMCBCs prepared with flake graphite powders that were evenly loaded with tungsten copper composite powder(RMCBCs-W@Cu)exhibited a low wear rate of 1.63 mm^(3)/h,exhibiting 48.6%reduction in the wear rate relative to RCMBCs without additives(RMCBCs-0).In addition,RMCBCs-W@Cu achieved a low friction coefficient of 0.243 and low electric spark grade.These findings indicate that tungsten copper composite powders provide particle reinforcement and generate a gradation effect for the epoxy resin(i.e.,connecting phase)in RMCBCs,which weakens the wear of RMCBCs caused by fatigue under a cyclic current-carrying wear.
基金supported by the Science and Technology Development Fund (2015B0201025)the key subject "Computational Solid Mechanics" of China Academy of Engineering Physics+1 种基金the National Outstanding Young Scientists Foundation of China (11225213)the National Natural Science Foundation of China (11521062,11602258)
文摘In the present manuscript numerical analysis on the ballistic performance of a tungsten particle/metallic glass matrix(WP/MG) composite rod is conducted by integrating with related experimental investigations. In the corresponding finite element method(FEM) simulations a modified coupled thermomechanical constitutive model is employed to describe the mechanical properties of metallic glass(MG)matrix, and geometrical models of the WP/MG composite rod are established based on its inner structure. The deformation and failure characteristics of the rod and target materials are analyzed in detail,and the influences of various factors on the ballistic performance of the WP/MG composite long rod are discussed. Related analysis demonstrates that the penetrating performance of the WP/MG rod is similar to that of the tungsten fiber/metallic glass matrix(WF/MG) composite long rod, i.e., a "self-sharpening" behavior also occurs during the penetration process, and correspondingly its penetrating capability is better than that of the tungsten heavy alloy(WHA) rod. However, the mass erosion manner of the WP/MG rod is different and the erosion is relatively severe, thus its penetrating capability is a little lower compared with that of the WF/MG one. Moreover, the impact velocity and the target strength have significant influences on the ballistic performance of the WP/MG composite rod, whereas the effect of initial nose shape is very little.
文摘In this study,a mathematical model was developed to optimize the heat treatment process for maximum tensile strength and ductility of aluminum(8011) silicon carbide particulate composites.The process parameters are solutionizing time,aging temperature,and aging time.The experiments were performed on an universal testing machine according to centre rotatable design matrix.A mathematical model was developed with the main and interactive effects of the parameters considered.The analysis of variance technique was used to check the adequacy of the developed model.The optimum parameters were obtained for maximum tensile strength.Fractographic examination shows the cracks and dimples on the fractured surfaces of heat-treated specimen.
基金financial support received from Fonds Québécois de la Recherche sur la Nature et les Technologies (FQRNT)
文摘Titanium metal matrix composite(Ti-MMC)has excellent features and capabilities which can be considered a potential candidate to replace commercial titanium and superalloys within an extensive range of products and industrial sectors.Regardless of the superior features in Ti-MMC,however,referring to several factors including high unit cost and existence of rigid and abrasive ceramic particles in the generated matrices of the work part,the Ti-MMC is grouped as extremely difficult to cut with a poor level of machinability.Furthermore,adequate process parameters for machining Ti-MMCs under several lubrication methods are rarely studied.Therefore,adequate knowledge of this regard is strongly demanded.Among machinability attributes,ultrafine particles(UFPs)and fine particles(FPs)have been selected as the main machinability attributes and the factors leading to minimized emission have been studied.According to experimental observations,despite the type of coating used,the use of higher levels of flow rate led to less UFPs,while no significant effects were observed on UFPs.Under similar cutting conditions,higher levels of FPs were recorded under the use of uncoated inserts.Moreover,cutting speed had no significant influence on UFPs;nevertheless,it significantly affects the FPs despite the type of insert used.
文摘电子信息系统小型化、轻量化、无人化、一体化的发展趋势要求电子封装持续减小尺寸、降低重量和减少功耗(SWaP,即Size,Weight and Power)。传统的基于可伐合金、铝合金和高硅铝的微电子封装材料难以同时满足大跨度热匹配、良好的钎焊与激光熔焊性能、高导热、高比刚度、高比强度和良好的可制造性,无法适应SWaP要求。功能梯度铝基复合材料综合了铝合金与铝硅、碳化硅铝等先进复合材料的优点,既具备大跨度热匹配、高导热率的特点,又具备精细加工和良好的激光熔焊等工艺性能,是新一代微电子封装材料的研究热点。本文综述了功能梯度铝基复合材料的优势、制备方法和封装应用情况,并对该材料制备与应用中存在的问题进行了总结,最后对其未来研究方向进行了展望。
