有关金属表层X射线应力分析的讨论

Some Discussions on Metal X-Ray Macrostress Measurement

本文提出全属表面附近层区的三维应力的新的测试方法,对于存在应力梯度的金属表面层研究有着特殊的意义。本文在X射线宏观应力测试中采用非线性回归方法,较之常规应力测试的线性回归方法,可以得到更具合理性的应力参数,这些应力参数所表示的是金属表面厚度约(1.1～1.2)H_0范围内的平均值。这里,H_0=sinθ_■/μ定义为能够产生X射线衍射的表面层的有效厚度,μ是X射线的线衰减系数。分析表明,自由表面附近的法向正应力ν_(33)≈0。

A new X-ray technique has been demonstrated, which permits the evaluation of the three dimensional stress states in near surface regions. It will be of particular interest in studies of some metal surface layers in which the stress gradients exist. Nonlinear regression method of X-ray macrostress measurement as mention in this paper can get more rational results of stress components than linear regression of ordinary stress measurement. These stress components are the mean value in surface layers about (1.1—1.2)H_0 thick, here, H_0=sinθ_(φ0)/μ is defined as an effective thickness of the surface layers which can produce X-ray diffraction, and μ is the linear absorption coefficient of X-ray. Analysis shows that the normal stress σ_(33)≈0 in free surface layers.