摘要
为准确掌握铝合金搅拌摩擦焊(Friction stir welding,FSW)焊件中的残余应力分布,以便优化FSW焊接工艺和对后续加工起到一定的支撑作用,借助自主研发的短波长特征X射线衍射仪(Short wavelength X-ray diffractometer,SWXRD),分别采用sin2ψ法和d0法对2024-T351铝合金FSW焊件内部残余应力进行测试,并与中子衍射和同步辐射及钻孔法测试的FSW焊接应力进行分析比较,同时对焊接区各区域微观组织进行金相观察分析,对焊接中心层的显微硬度分布进行测试。结果表明,用SWXRD可以实现铝合金内部残余应力的无损检测;对2024-T351铝合金FSW焊件内部残余应力测试,用d0法得到板材轧制方向的残余应力存在3个拉应力峰值,其中两个位于热影响区(Heat affected zone,HAZ),一个位于焊缝中心,与国外中子衍射和高能同步辐射的测试结果一致;用sin2ψ法可以快速获得FSW焊核区(Weld nugget zone,WNZ)的残余应力,对存在强织构的热机械影响区(Thermal-mechanically affected zone,TMAZ)、HAZ和母材区(Base material zone,BMZ)的应力测试有较大的误差,但将d0法结合可以快速得到焊接区的应力分布。
In order to optimize the process of friction stir welding（FSW） and supply the information to the further machine, it is significant to measure the residual stress distribution in the FSW weldment of A1 alloy. A domestic invented short wavelength X-ray diffractometer（SWXRD） is employed to determine the internal residual stresses in 2024-T351 A1 alloy FSW weldment using both do mode and sin^2ψ mode. The residual stress distribution results which obtained using SWXRD, neutron diffraction and high energy synchrotron respectively are compared and analyzed. Meanwhile the microstructure in the weldment is observed and the hardness in the center layer of plate is measured. The results show that the internal residual stress in A1 alloy FSW can be determined by SWXRD As for 2024-T351 A1 alloy weldment, there are three tensile stress peaks, two tensile peaks located in the heat affected zone（HAZ） and another on the weld line. The result of do mode is identical with results of other methods such as neutron diffraction and synchrotron diffraction. The stress distribute in the weld nugget zone（WNZ） of the FSW weldment determined using sin^2ψ mode fit well with the result of do mode. However the sin^2ψ mode can not used to measure the stress distribution in the other zone such as thermal-mechanically affected zone（TMAZ）, HAZ and base material zone（BMZ） due to strong texture. It is an applicable method to determine internal residual stresses combined sin^2ψ and do mode together by SWXRD.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2013年第2期28-34,共7页
Journal of Mechanical Engineering
基金
国家自然科学基金(51275037)
国家高技术研究发展计划(863计划
2009AA03Z539)资助项目
关键词
短波长
X射线衍射
内部
残余应力
搅拌摩擦焊
铝合金
Short wavelength X-ray diffraction Intemal Residual stresses Friction stir welding Aluminum alloys
