热处理工艺和热变形参数对Ti-20Zr-6.5Al-4V合金组织与性能的影响

发布时间：2018-12-27 15:55

【摘要】：钛及钛合金具有高的比强度、淬透性、延展性、耐腐蚀性及耐高温性能,是一种非常重要的新型金属结构材料,广泛应用于航空航天、能源、冶金、军事、医疗、化工以及海洋石油开采等方面。但是钛合金的耐磨性能较差,极大地限制了钛合金应用范围。锆具有低的密度和良好的耐腐蚀性、耐磨性、抗辐射诱发蠕变以及适中的力学性能。为了改善钛合金的力学性能,通过添加Zr元素设计了一系列的新型Ti Zr Al V合金,这些合金都拥有优异的力学性能。其中Ti-20Zr-6.5Al-4V是最优组成,本文以Ti-20Zr-6.5Al-4V合金作为研究对象,研究了热处理工艺以及热变形参数对Ti-20Zr-6.5Al-4V合金的组织及力学性能的影响,以便通过控制热处理工艺和热变形参数得到期望的合金性能。结果表明,Ti-20Zr-6.5Al-4V钛合金经850~1000?C固溶处理后得到一种α?+β的双相组织,随着固溶温度的升高,α?相的含量逐渐减少,其尺寸也不断的变小,β相晶粒尺寸不断增大。固溶处理时,α?相首先从晶界析出,时效处理过程中发生α?→β以及β→α相转变。Ti-20Zr-6.5Al-4V钛合金经过固溶处理后其抗压强度和压缩收缩率较高,屈服强度较低,时效处理后其真屈服强度显著提高,其真抗压强度略有提高,而其压缩收缩率明显减小。Ti-20Zr-6.5Al-4V钛合金经过不同冷却速率、变形量和变形温度的处理后的组织由α相和β相两相组成。随变形温度的升高,α相的尺寸增加,随冷却速率的增大,α相的含量不断减少,变形抑制了β→α相的转变。随着冷却速率和变形量的增大,合金的硬度增加。
[Abstract]:Titanium and titanium alloys have high specific strength, hardenability, ductility, corrosion resistance and high temperature resistance, are a very important new type of metal structural materials, widely used in aerospace, energy, metallurgy, military, medical, Chemical and offshore oil extraction and other aspects. However, the wear resistance of titanium alloy is poor, which greatly limits the application range of titanium alloy. Zirconium has low density and good corrosion resistance, wear resistance, radiation induced creep resistance and moderate mechanical properties. In order to improve the mechanical properties of titanium alloys, a series of new Ti Zr Al V alloys were designed by adding Zr elements. These alloys have excellent mechanical properties. Ti-20Zr-6.5Al-4V is the optimal composition. In this paper, the effects of heat treatment and thermal deformation parameters on the microstructure and mechanical properties of Ti-20Zr-6.5Al-4V alloy were studied. In order to obtain the desired properties of the alloy by controlling the heat treatment process and the hot deformation parameters. The results showed that Ti-20Zr-6.5Al-4V titanium alloy was treated with 850U 1000C solution to obtain a kind of dual phase structure of 伪? 尾. With the increase of solution temperature, 伪? The content of phase decreases gradually, and the size of 尾 phase becomes smaller, and the grain size of 尾 phase increases. In solution treatment, 伪? The phase first precipitated from grain boundary, and the 伪-尾 and 尾-伪 phase transition occurred during aging treatment. The compressive strength and compression shrinkage of Ti-20Zr-6.5Al-4V titanium alloy were higher and the yield strength was lower after solution treatment. After aging treatment, the true yield strength increased significantly, the true compressive strength slightly increased, and the compression shrinkage decreased obviously. The Ti-20Zr-6.5Al-4V titanium alloy was cooled at different cooling rates. The microstructure after the treatment of deformation amount and deformation temperature is composed of 伪 phase and 尾 phase. With the increase of deformation temperature, the size of 伪 phase increases, and the content of 伪 phase decreases with the increase of cooling rate. The hardness of the alloy increases with the increase of cooling rate and deformation.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG166.5

【相似文献】