两相钛合金TC16衍射峰形分析与织构测定

Diffraction Peak Profile Analysis and Texture Measurement of a Two-phase Titanium Alloy TC16

摘要:

TC16(Ti-3Al-5Mo-4.5V)钛合金的?相(0002)和?相(110)衍射峰位差小于0.1°，由于?相含量增多，在传统的X衍射织构测试光路中两峰重叠严重，目前?+?两相TC16钛合金织构无法测量。本文对热轧退火态TC16钛合金棒材进行重叠衍射峰分离操作，通过光学显微镜、X射线衍射仪、维氏硬度计对TC16合金的显微组织、织构和力学性能进行了研究。在Matlab平台上借助柯西平方函数拟合衍射峰形，依据α相衍射峰和β相衍射峰的展宽和重叠影响程度，考察衍射光路参数改变对其产生的影响。结果表明：利用多导毛细管和平行长索拉狭缝的X射线衍射光路配置，解决了衍射峰重叠问题，提高了织构测定的准确性；测试发现，热轧退火态TC16棒材中主要存在两种织构组分，为<0002>和<101(-)0>双重丝织构；织构的存在使TC16横向抗拉强度小于纵向抗拉强度，讨论了织构对钛合金机械性能的影响。本研究对于提高钛合金紧固件的性能和加工工艺具有重要理论和工程意义，同时，也为两相钛合金织构的准确测定提供一种解决方案。

Abstract:

The difference between the diffraction peak position of α phase (0002) and β phase (110) of TC16 (Ti-3Al-5Mo-4.5V) titanium alloy is less than 0.1°. Due to the increase of β phase content, the two peaks overlap severely in the traditional X-ray diffraction test optical path. At present, the α+β two-phase TC16 titanium alloy texture cannot be measured. In this paper, overlapping diffraction peaks were separated from the hot rolled annealed TC16 titanium alloy bar diffraction pattern. The microstructure, texture and mechanical properties of TC16 alloy bar were studied by optical microscope, X-ray diffraction and Vickers hardness tester. The shape of the diffraction peak was fitted by the Cauchy square function on the Matlab platform, and the influence of the change of diffraction optical path parameters on the broadening and overlapping of the α phase diffraction peak and the β phase diffraction peak was investigated. The results show that the X-ray diffraction optical path configuration of the polycapillary and parallel long sola slit solves the problem of overlapping diffraction peaks and improves the accuracy of texture measurement; The test found that there are mainly two texture components in hot rolled annealed TC16 bar, which are <0002> and <101(-)0> double wire texture; The texture makes the transverse tensile strength of TC16 less than the longitudinal tensile strength, the effects of texture on the mechanical properties of titanium alloy are discussed. This research has important theoretical and engineering significance for improving the performance and processing technology of titanium alloy fasteners. At the same time, it also provides a solution for the accurate measurement of the texture of two-phase titanium alloys.