两种不同热处理工艺下亚稳β钛合金Ti-6Mo-5V-3Al-2Fe-2Zr的低周疲劳行为  

Low-Cycle Fatigue Behavior of Metastable β Titanium Alloy Ti-6Mo-5V-3Al-2Fe-2Zr with Two Kinds of Heat Treatment

作　　者：刘知多 张浩宇[1] 周舸 程军[2] 张兴君 陈立佳[1] Liu Zhiduo;Zhang Haoyu;Zhou Ge;Cheng Jun;Zhang Xingjun;Chen Lijia(Shenyang University of Technology,Shenyang 110870,China;Northwest Institute for Nonferrous Metal Research,Xi’an 710016,China;Shenyang Branch,Liaoning North Precision Equipment Co.,Ltd,Shenyang 110000,China)

机构地区：[1]沈阳工业大学,辽宁沈阳110870 [2]西北有色金属研究院,陕西西安710016 [3]辽宁北方精密设备有限公司沈阳分公司,辽宁沈阳110000

出　　处：《稀有金属材料与工程》2023年第2期658-666,共9页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(52104379,U21A20117);辽宁省教育厅青年科技人才“育苗”项目(LQGD2020012);辽宁省“揭榜挂帅”科技攻关项目(2021JH1/10400069)。

摘　　要：研究了固溶+等温时效及固溶+随炉冷却2种不同热处理工艺下Ti-6Mo-5V-3Al-2Fe-2Zr(质量分数,%)合金的低周疲劳行为。结果显示:固溶+等温时效处理后的M1合金显微组织中含有短棒状的晶内α相以及连续晶界α相;固溶+随炉冷却处理后得到的M2合金显微组织中含有细长针状的晶内α相、连续晶界α相以及WGBα相。在0.6%、0.7%和0.8%的较低应变幅下M1合金和M2合金均呈现出循环稳定的现象,晶内α相间距较小的M2合金呈现出较高的应力幅值;在1.0%的较高应变幅下,由于背应力和摩擦应力的竞争机制,导致M1合金和M2合金均呈现循环软化现象。在0.9%和1.0%的较高应变幅下M2合金的背应力硬化速率相对较小,其循环软化现象更加明显,其应力幅值相对较低。M2合金的晶内α相将基体分割为若干“封闭单元”且β晶界处形成了向晶内平行生长的WGBα相,导致其低周疲劳寿命均低于M1合金。The low-cycle fatigue behavior of Ti-6Mo-5V-3Al-2Fe-2Zr alloy under two different heat treatment processes of solution+isothermal aging and solution+furnace cooling was studied. The results show that the microstructure of M1 alloy after solution+isothermal aging treatment contains short rod-like intracrystalline α phase and continuous grain boundary α phase. The microstructure of M2 alloy obtained after solid solution+furnace cooling treatment contains elongated acicular intragranular α phase, continuous grain boundary α phase and WGB α phase. M1 and M2 alloys exhibit cyclic stability at low strain amplitudes of 0.6%, 0.7% and 0.8%, and M2 alloy with smaller intracrystalline α phase spacing exhibits higher stress amplitudes. At a high strain amplitude of 1.0%, due to the competitive mechanism of back stress and friction stress, both M1 and M2 alloys exhibit cyclic softening. Under high strain amplitudes of 0.9% and 1.0%, the back stress hardening rate of M2 alloy is relatively small, the cyclic softening phenomenon is more obvious, and the stress amplitude is relatively low. The intracrystalline α phase of M2 alloy divides the matrix into several “ closed units ” and forms a WGB α phase parallel to the intracrystalline at the β grain boundary, resulting in lower cycle fatigue life than M1 alloy.

关 键 词：亚稳Β钛合金 随炉冷却 低周疲劳行为 摩擦应力 背应力 

分 类 号：TG146.23[一般工业技术—材料科学与工程] TG166.5[金属学及工艺—金属材料]