在对5A06铝合金板进行X-ray残余应力检测时发现，其表面包铝层会对衍射图样造成干扰，尤其是衍射峰峰位会发生较大偏移。为了获得独立的包铝层与基体的衍射峰峰位，选取表面覆有包铝层且厚度大于试验用Co靶K_α射线透射深度的5A06铝合金板，与去除包铝层后的5A06铝合金板作为试验对象，并以纯铝板作为参考，进行了三者的衍射峰峰位检测试验。试验结果表明，包铝层与基体5A06铝合金衍射峰峰位所对应探测器通道数的差值约为90，而与纯铝相同。由此结果，从布拉格衍射定律入手分析了残余应力、干涉级数、设备操作因素与衍射峰峰位偏移量的关系；以晶胞为衍射单元，列举可发生衍射的晶面，并给出衍射晶面指数变化与衍射峰峰位偏移量的关系。通过分析，确定晶格常数差异是引起两者衍射峰峰位差异的原因。

During the X-ray residual stress detection of 5A06 aluminum alloy plate, it was found that the aluminum layer of its surface would interfere with the diffraction pattern, especially the diffraction peak position. In order to obtain independent package aluminum layer and substrate diffraction peak position, this article firstly selected package aluminum with its layer thickness being greater than the ray transmission depth of 5A06 aluminum alloy plate, and then removed the package aluminum layer of 5A06 aluminum alloy as experimental object, and pure aluminum sheet for reference. By doing so, an experimental test on diffraction peak position was carried out by the above-mentioned three. The experimental results showed that the difference of the number of detector channels was about 90, which was the same as that of pure aluminum. From the result, the author analyzed the relationship between residual stress, interference series, equipment operation factors and the diffraction peak position deviation based on Bragg diffraction law. In this paper, the crystal surface of diffraction is enumerated, and the relation between the diffractive crystal surface exponent and the diffraction peak deviation is given. By analysis, the cause of the difference between the two diffraction peaks was due to the difference of lattice constants.