X射线衍射测试PDC表面残余应力的实验研究

Experimental study on measuring residual stresses of PDC by X-ray diffraction

作者采用DIMAX2500型X射线衍射仪,通过对入射光狭缝尺寸进行调整,使X射线的照射光斑尺寸缩小为1.5×5 mm,从而实现了对PDC表面沿径向的四个不同位置的应力测量。测量采用sin2ψ法,不但测出了PDC表面不同位置的残余应力,还由此得到了PDC表面应力沿径向的分布规律,而且这一测试结果与通过有限元分析计算出的应力分布趋势基本吻合。作者还对测试值与有限元分析计算值出现偏差的原因从测试方法、有限元分析参数取值及样品表面加工方式等几方面进行了分析讨论。

The residual stresses were measured in four different positions along the radial direction of PDC by using DIMAX2500 X-ray apparatus in this study. The size of incident beam slit was adjusted to make the diffraction spot shrink to 1.5 ~ 5 mm. Thus the residual stresses of PDC and their radial distribution were obtained. A finite element analysis （FEA） of the PDC tested in the experiment was made to check the validity of the testing results. The FEA model result was found to correlate well with the measured values. Factors leading to the deviation between XRD experimental measurements and calculations of residual stress by FEA were analyzed, which are： the limitation of the testing method, the choice of FEA parameters, and the treatment of the sample.