采用ASTM D 5961标准试验方法对M21/T800复合材料挤压性能进行研究。对不同层压板厚度、不同环境以及不同紧固件类型下的层压板挤压试验结果进行了比较,对层压板挤压强度和破坏模式进行了总结。结果表明,由于层压板的厚度和孔形式不同,...采用ASTM D 5961标准试验方法对M21/T800复合材料挤压性能进行研究。对不同层压板厚度、不同环境以及不同紧固件类型下的层压板挤压试验结果进行了比较,对层压板挤压强度和破坏模式进行了总结。结果表明,由于层压板的厚度和孔形式不同,单钉单搭接的极限挤压强度在433.6～856 MPa间,即最低值和最高值分别为433.6 MPa和856 MPa,差值接近一倍;M21/T800复合材料的挤压强度受环境影响不大;常温和湿热环境挤压强度相当;板厚较小的层压板挤压强度受钉类型的影响比较大,最大挤压强度差值为174.01 MPa。展开更多
The cyclic extrusion compression （CEC） process was introduced into the AM60B magnesium alloy. The use of the CEC process was favorable for producing finer microstructures. The results show that the microstructure ca...The cyclic extrusion compression （CEC） process was introduced into the AM60B magnesium alloy. The use of the CEC process was favorable for producing finer microstructures. The results show that the microstructure can be effectively refined with increasing the number of CEC passes. Once a critical minimum grain size was achieved, subsequent passes did not have any noticeable refining effect. As expected, the fine-grained alloy has excellent mechanical properties. The micro-hardness, yield strength, ultimate tensile strength and elongation to failure of two-pass CEC formed alloy are 72.2, 183.7 MPa, 286.3 MPa and 14.0%, but those of as-cast alloy are 62.3, 64 MPa, 201 MPa and 11%, respectively. However, there is not a clear improvement of mechanical properties with further increase in number of CEC passes in AM60B alloy. The micro-hardness, yield strength, ultimate tensile strength and elongation to failure of four-pass CEC formed alloy are 73.5, 196 MPa, 297 MPa and 16%, respectively.展开更多
The 6061 aluminum matrix composites reinforced with ZnO-coated Mg_2B_2O_5w were fabricated by squeeze casting method and followed by extruded under a technical equivalent condition. The mechanical properties and micro...The 6061 aluminum matrix composites reinforced with ZnO-coated Mg_2B_2O_5w were fabricated by squeeze casting method and followed by extruded under a technical equivalent condition. The mechanical properties and microstructures of the composites were investigated. The results showed that the elastic modulus of the as-cast composites increased straightly with increasing ZnO coating content. The ultimate tensile strength and yield strength of the as-cast composites rapidly increased initially and then declined with increasing ZnO coating content. However, the elongations of all the as-cast composites had similar values. The elongations of the composites were highly enhanced and the ultimate tensile strength of the composite without ZnO coating was the largest after extrusion. A number of whiskers in the composites with ZnO coating were fractured during the extrusion process, but the whiskers＇ breakage extent was limited with the increase of coating content.展开更多
TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing （ECAP） at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the func...TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing （ECAP） at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the functional properties. The effects of both thermodynamically stable and metastable second phases on the mechanical properties and martensitic transformations of these alloys were investigated. It is found that thermodynamically stable Ti2Ni phase has no effect on martensitic transformation and superelasticity of Ti-rich TiNi alloy, thermodynamically stable α phase is harmful for ductility of Ti-Mo-Nb-V-Al alloy, but metastable Ti3Ni4 phase is effective for R phase transformation, martensitic transformation and superelasticity of Ni-rich TiNi alloy. The mechanisms of the second phases on the martensitic transformations and mechanical properties were discussed.展开更多
基金Projects(ZD20081901,QC2010110,QC2012C006)supported by the Natural Science Foundation of Heilongjiang Province,ChinaProject(2012RFQXS113)supported by Special Fund Project for Scientific and Technological Innovation Talents of Harbin,ChinaProject(201210214008)supported by Training Programs of Innovation and Entrepreneurship for Undergraduates,China
文摘The cyclic extrusion compression （CEC） process was introduced into the AM60B magnesium alloy. The use of the CEC process was favorable for producing finer microstructures. The results show that the microstructure can be effectively refined with increasing the number of CEC passes. Once a critical minimum grain size was achieved, subsequent passes did not have any noticeable refining effect. As expected, the fine-grained alloy has excellent mechanical properties. The micro-hardness, yield strength, ultimate tensile strength and elongation to failure of two-pass CEC formed alloy are 72.2, 183.7 MPa, 286.3 MPa and 14.0%, but those of as-cast alloy are 62.3, 64 MPa, 201 MPa and 11%, respectively. However, there is not a clear improvement of mechanical properties with further increase in number of CEC passes in AM60B alloy. The micro-hardness, yield strength, ultimate tensile strength and elongation to failure of four-pass CEC formed alloy are 73.5, 196 MPa, 297 MPa and 16%, respectively.
基金Project(2011CB612200)supported by the National Basic Research Program of China
文摘The 6061 aluminum matrix composites reinforced with ZnO-coated Mg_2B_2O_5w were fabricated by squeeze casting method and followed by extruded under a technical equivalent condition. The mechanical properties and microstructures of the composites were investigated. The results showed that the elastic modulus of the as-cast composites increased straightly with increasing ZnO coating content. The ultimate tensile strength and yield strength of the as-cast composites rapidly increased initially and then declined with increasing ZnO coating content. However, the elongations of all the as-cast composites had similar values. The elongations of the composites were highly enhanced and the ultimate tensile strength of the composite without ZnO coating was the largest after extrusion. A number of whiskers in the composites with ZnO coating were fractured during the extrusion process, but the whiskers＇ breakage extent was limited with the increase of coating content.
基金Project (50671067) supported by the National Natural Science Foundation of ChinaProject (09JC1407200) supported by the Science and Technology Committee of Shanghai, China
文摘TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing （ECAP） at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the functional properties. The effects of both thermodynamically stable and metastable second phases on the mechanical properties and martensitic transformations of these alloys were investigated. It is found that thermodynamically stable Ti2Ni phase has no effect on martensitic transformation and superelasticity of Ti-rich TiNi alloy, thermodynamically stable α phase is harmful for ductility of Ti-Mo-Nb-V-Al alloy, but metastable Ti3Ni4 phase is effective for R phase transformation, martensitic transformation and superelasticity of Ni-rich TiNi alloy. The mechanisms of the second phases on the martensitic transformations and mechanical properties were discussed.
