基于等通道转角挤压的V-5Cr-5Ti合金晶粒细化机理  

Grain Refinement Mechanism of V-5Cr-5Ti Alloy Based on Equal Channel Angular Pressing

作　　者：黄姝珂[1] 李敬民[1] 孟玉堂[1] 张永皞[1] 刘建辉[1] 李昌安[1] 

机构地区：[1]中国工程物理研究院,四川绵阳621900

出　　处：《稀有金属材料与工程》2016年第9期2313-2316,共4页Rare Metal Materials and Engineering

基　　金：中国工程物理研究院科学技术发展基金(2014B0302044)

摘　　要：研究了用等通道转角挤压(ECAP)技术处理V-5Cr-5Ti合金的可行性,并分析了后续退火处理对合金硬度和微观组织的影响规律,进而探讨了合金的晶粒细化机理。ECAP采用相关模具在万能材料试验机上进行,在真空炉中进行退火,利用维氏硬度计进行硬度测试,采用X射线衍射(XRD)分析相结构,光学显微镜(OM)观察微观组织。结果表明,在室温下V-5Cr-5Ti合金可以顺利进行2道次ECAP过程,后续配合950℃以上温度退火,晶粒尺寸可以从约100μm细化到约30μm。V-5Cr-5Ti合金的晶粒细化机理不同于传统体心立方合金,在挤压过程中,原始晶粒发生自转动,原始晶界清晰可见,未被碎化,但晶内出现大量的剪切滑移带。在后续退火过程中,细小晶粒在原始晶粒内部的剪切滑移带上形成,最终原始晶界和形成的细小晶界逐渐难以区分,形成整体的细晶组织。The feasibility of equal channel angular pressing（ECAP） for treating V-5Cr-5Ti alloy was investigated. The effect of annealing treatment on the hardness and grain refinement mechanism of the alloy was analyzed. ECAP was performed using pressing dies and a universal material testing machine. The annealing was done in a vacuum heat treatment furnace. The hardness was tested using a Vickers hardness tester. The phase structure was identified using X-ray diffraction（XRD）. The microstructure was observed using optical microscope（OM）. The results indicate that the grain size of V-5Cr-5Ti alloy can be refined from ～100 μm to ～30 μm after two times ECAP and annealing above 950 ℃. It is different from the traditional grain refinement mechanism of bcc alloy. The grains of V-5Cr-5Ti alloy are rotated on itself in ECAP process, and a lot of shearing glide bands are formed in coarse grains. With the annealing temperature increasing, fine grains are formed gradually at shearing glide bands and the initial grain boundaries are still clear. Finally, the fine grains are formed completely above 950 ℃, and the initial grain boundaries become blurred gradually.

关 键 词：V-5Cr-5Ti合金 等通道转角挤压 晶粒细化 

分 类 号：TG379[金属学及工艺—金属压力加工]