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将X射线法(XRD)的绝对应力测量评定转化为相对应力测量评定,以测量精确度和重复性为评价指标,对各种定峰方法的优劣性进行研究。实验证明,交相关法通过逐差法利用全部衍射峰信息,直接获取XRD法所需的布拉格角差值,有最好的测量精度和重复性。最大值法和抛物线法利用峰顶信息,具有较高的应力测量精度,但由于信息利用区间较窄,测量重复性较差,半高宽法(FWHM)测量精度和重复性很差,不适于对铝合金定峰。远离布拉格角处信息对重心法影响很大,对衍射峰的预处理要求也高,力臂的存在使得测量精度变差;力臂和波谱边缘随机性使测量重复性很差。交相关法对铝合金X射线应力测量有最好的定峰效果。
X-ray method (XRD) absolute stress measurement assessment into relative stress measurement assessment, measurement accuracy and repeatability as the evaluation index, the advantages and disadvantages of various fixed peak method were studied. Experiments show that the cross-correlation method uses the full diffraction peak information by the difference method to directly obtain the Bragg angle difference required by the XRD method, and has the best measurement accuracy and repeatability. Maximum method and parabolic method make use of the peak information and have high precision of stress measurement. However, due to the narrow information utilization range and poor repeatability of measurement, FWHM measurement accuracy and repeatability are not suitable The peak of the aluminum alloy. The information far from the Bragg corner has a great influence on the gravity center method, and the pretreatment of the diffraction peak is also high. The presence of the force arm makes the measurement accuracy worse; the randomness of the arm and the spectrum edge makes the measurement repeatability very poor. Cross-correlation method for aluminum alloy X-ray stress measurement has the best peak-fixing effect.