预拉伸变形量对7055铝合金厚板表面残余应力的影响

为了系统性地研究预拉伸变形量对淬火残余应力的消减规律,采用基于cosα法的μ-X360s型X射线残余应力分析仪,表征7055铝合金厚板经不同预拉伸变形量(0%、0.5%、1.2%、1.5%、2.5%、3.3%、3.9%)的表面残余应力水平,并通过基于sin2Ψ法的X射线衍射法和钻孔法验证测试结果。结果表明:7055铝合金厚板经过固溶淬火处理后,残余应力水平较高,轧向分应力略小于横向分应力,在厚板边缘区域残余应力水平波动较大,波动区域大约在距边部27mm的位置。当预拉伸变形量为1.5%时,轧向分应力的明显减小,继续增大拉伸量,残余应力稳定在60~70 MPa;而当预拉伸变形量大约为1.5%时,横向分应力由压应力状态转变为拉应力状态;经超过2.5%的预拉伸变形后,残余应力稳定在20~30 MPa。

Influence of pre-stretched ratio on surface residual stress of 7055 aluminum alloy thick plate

In order to systematically study the reduction rule of quenched residual stress caused by pre-stretched systematically,the surface residual stresses of 7055 aluminum alloy thick plate with different pre-strectched ratios(0%,0.5%,1.2%,1.5%,2.5%,3.3%,3.9%)were characterized by theμ-X360s X-ray residual stress analyzer based on cosαmethod,and the measured results were verified by X-ray diffractometry based on sin2Ψmethod and hole drilling method.The results show that the residual stress of 7055 aluminum alloy thick plate is relatively high than that of the alloy after solution-quenched treatment,the rolling residual stress is slightly less than the transverse residual stress.The residual stress fluctuates greatly at the edge area of thick plate,and the fluctuation area is about 27 mm away from the edge.When the pre-stretched ratio is 1.5%,the rolling residual stress decreases obviously.The residual stress is stable at 6070 MPa with increasing the pre-stretched ratio.When the pre-stretched ratio is about 1.5%,the transverse residual stress changes from compressive stress to tensile stress,and when the pre-stretched ratio is more than 2.5%,the residual stress is stable at 2030 MPa.