不同氧含量TC4热挤压管材热处理强化工艺研究

Study on Heat Treatment Strengthening Technology of Hot Extruded Tube with Different Oxygen Content TC4

摘要: 本文对高低氧TC4钛合金挤压管材分别进行固溶处理和固溶时效处理来研究其热处理工艺强化。固溶处理表明，高低氧TC4钛合金热挤压管材在固溶水冷过程中均得到初生α相和α’ (细针状马氏体)组织，随着固溶温度提高初生α相含量下降和α’相的含量提高，同时随着氧含量提高固溶后的初生等轴α相晶粒尺寸增大，α’相含量降低。固溶时效处理表明，高低氧TC4钛合金挤压管材固溶时效热处理时发生α’马氏体分解，显微组织存在弥散析出物，该弥散析出物对TC4管材起到弥散强化的作用且随温度提高弥散程度加强，析出物增多。高低氧TC4钛合金挤压管材固溶时效处理后性能显著提高，这得益于针状α’马氏体在时效过程中发生分解析出物起到弥散强化的作用，从而提升材料的综合力学性能。

Abstract: In this paper, the heat treatment of high and low oxygen TC4 titanium alloy extruded pipe was strengthened by solution treatment and solution aging treatment respectively. The solid solution treatment shows that the primary α phase and α’ (fine acicular martensite) microstructure of the high and low oxygen TC4 titanium alloy hot extrusion pipe are obtained during the solid solution water cooling process. The primary α phase content decreases and α’ phase content increases with the increase of solution temperature, and the primary isaxed α phase grain size increases with the increase of oxygen content. The results show that α’ martensitic decomposition occurs during the solution aging heat treatment of high and low oxygen TC4 titanium alloy extrusion pipe, and there are dispersive precipitates in the microstructure. The dispersive precipitates play a role in strengthening the dispersion of TC4 pipe, and the degree of dispersion is strengthened with the increase of temperature. The properties of high and low oxygen TC4 titanium alloy extruded pipe are significantly improved after solution aging treatment, which is due to the dispersion strengthening effect of the acicular α’ martensite decomposition precipitates during the aging process, thus improving the comprehensive mechanical properties of the material.