采用扫描电镜、X射线衍射分析等手段 ,研究了正火处理对Cu Al Be B合金组织、相结构及阻尼和力学性能的影响 ,并原位观察拉伸应力作用下裂纹的萌生和扩展过程。研究结果表明 ,Cu Al Be B合金具有较高的阻尼性能 (S D C =17%～ 19% ) ,...采用扫描电镜、X射线衍射分析等手段 ,研究了正火处理对Cu Al Be B合金组织、相结构及阻尼和力学性能的影响 ,并原位观察拉伸应力作用下裂纹的萌生和扩展过程。研究结果表明 ,Cu Al Be B合金具有较高的阻尼性能 (S D C =17%～ 19% ) ,正火处理可抑制α相的析出 ,并减少γ1′的混杂程度 ,从而进一步提高阻尼能力。各向弹性异性和相变应变差引起的晶界集中应力 ,导致Cu A1 Be B合金在拉伸条件下发生晶间断裂。正火处理不但纯净晶界 ,形成马氏体共格晶界 ,而且减小晶内γ1′马氏体与 β1′马氏体的混合程度 ,有利于减少晶界应力集中和可能萌生的晶界裂纹源 ,从而有效改善合金的塑性和强度。展开更多
To overcome the problems of fusion welding of aluminium alloys, the friction stir welding(FSW) is recognized as an alternative joining method to improve the mechanical and corrosion properties. Tool profile is one of ...To overcome the problems of fusion welding of aluminium alloys, the friction stir welding(FSW) is recognized as an alternative joining method to improve the mechanical and corrosion properties. Tool profile is one of the important variables which affect the performance of the FS weld. In the present work, the effect of tool profile on the weld nugget microstructure and pitting corrosion of AA2219 aluminium-copper alloy was studied. FSW of AA2219 alloy was carried out using five profiles, namely conical, square, triangle, pentagon and hexagon. The temperature measurements were made in the region adjacent to the rotating pin. It was observed that the peak temperature is more in hexagonal tool pin compared to the welds produced with other tool pin profiles. It is observed that the extensive deformation experienced at the nugget zone and the evolved microstructure strongly influences the hardness and corrosion properties of the joint during FSW. It was found that the microstructure changes like grain size, misorientation and precipitate dissolution during FSW influence the hardness and corrosion behaviour. Pitting corrosion resistance of friction stir welds of AA2219 was found to be better for hexagon profile tool compared to other profiles, which was attributed to material flow and strengthening precipitate morphology in nugget zone. Higher amount of heat generation in FS welds made with hexagonal profile tool may be the reason for greater dissolution of strengthening precipitates in nugget zone.展开更多
文摘采用扫描电镜、X射线衍射分析等手段 ,研究了正火处理对Cu Al Be B合金组织、相结构及阻尼和力学性能的影响 ,并原位观察拉伸应力作用下裂纹的萌生和扩展过程。研究结果表明 ,Cu Al Be B合金具有较高的阻尼性能 (S D C =17%～ 19% ) ,正火处理可抑制α相的析出 ,并减少γ1′的混杂程度 ,从而进一步提高阻尼能力。各向弹性异性和相变应变差引起的晶界集中应力 ,导致Cu A1 Be B合金在拉伸条件下发生晶间断裂。正火处理不但纯净晶界 ,形成马氏体共格晶界 ,而且减小晶内γ1′马氏体与 β1′马氏体的混合程度 ,有利于减少晶界应力集中和可能萌生的晶界裂纹源 ,从而有效改善合金的塑性和强度。
基金Project（2016YFB0300901） supported by the National Key R＆D Program of China Project（51421001） supported by the National Natural Science Foundation of China Project（2018CDJDCL0019） supported by the Fundamental Research Funds for the Central Universities, China
文摘To overcome the problems of fusion welding of aluminium alloys, the friction stir welding(FSW) is recognized as an alternative joining method to improve the mechanical and corrosion properties. Tool profile is one of the important variables which affect the performance of the FS weld. In the present work, the effect of tool profile on the weld nugget microstructure and pitting corrosion of AA2219 aluminium-copper alloy was studied. FSW of AA2219 alloy was carried out using five profiles, namely conical, square, triangle, pentagon and hexagon. The temperature measurements were made in the region adjacent to the rotating pin. It was observed that the peak temperature is more in hexagonal tool pin compared to the welds produced with other tool pin profiles. It is observed that the extensive deformation experienced at the nugget zone and the evolved microstructure strongly influences the hardness and corrosion properties of the joint during FSW. It was found that the microstructure changes like grain size, misorientation and precipitate dissolution during FSW influence the hardness and corrosion behaviour. Pitting corrosion resistance of friction stir welds of AA2219 was found to be better for hexagon profile tool compared to other profiles, which was attributed to material flow and strengthening precipitate morphology in nugget zone. Higher amount of heat generation in FS welds made with hexagonal profile tool may be the reason for greater dissolution of strengthening precipitates in nugget zone.
