Ti-6Al-4V-0.1B钛合金的热压缩变形行为  

Compression Deformation Behavior of Ti-6Al-4V-0.1B Titanium Alloy at Elevated Temperature

作　　者：黄立国[1] 庄伟彬[1] 高志玉[1] Huang Liguo;Zhuang Weibin;Gao Zhiyu(College of Materials Science and Engineering,Liaoning Technical University,Fuxin 123000,China)

机构地区：[1]辽宁工程技术大学材料科学与工程学院,辽宁阜新123000

出　　处：《稀有金属》2023年第4期512-519,共8页Chinese Journal of Rare Metals

基　　金：辽宁省自然科学基金项目(2019-ZD-0049)资助。

摘　　要：作为一种新型合金,Ti-6Al-4V-0.1B合金显示了较好的塑性成形能力及应用前景。通过真空感应凝壳熔炼方法制备了Ti-6Al-4V-0.1B合金铸锭,随后在850~985℃的温度范围内和0.001~1 s-1的应变速率范围内对Ti-6Al-4V-0.1B合金进行热压缩测试。运用真应力-真应变曲线研究了合金的流动行为。利用光学显微镜(OM)、扫描电镜(SEM)和电子背散射衍射技术(EBSD)对合金显微组织进行了表征。研究结果显示,Ti-6Al-4V-0.1B合金的流动应力对温度和应变速率都是敏感的,且温度对流动应力的影响比应变速率大。与基体合金相比,Ti-6Al-4V-0.1B合金具有更高的应力指数和应变激活能,这归因于分布在晶界处的TiB增加了原子扩散的阻力,减慢了热变形动态软化过程。热压缩过程中,初生α相发生了明显的球化,球化过程也受变形温度和应变速率的影响。由于TiB与基体之间的应变不匹配导致了高应变速率下合金基体的开裂,随后裂纹沿着定向排列的TiB粒子扩展,因此Ti-6Al-4V-0.1B合金的热加工过程应在低应变速率下进行。Ti-6Al-4V alloy has a small thermal conductivity,and its ingot grains are usually very coarse.The addition of a trace amount of B(0.1%,mass fraction)during the smelting process significantly refines the grains of Ti-6Al-4V through the constitutional undercooling mechanism.B element is distributed in the grain boundary in the form of TiB particles.Therefore,Ti-6Al-4V-0.1B alloy shows the possibility of direct plastic forming without the cogging process.In order to evaluate the influence of hot working process pa⁃rameters on alloy high temperature deformation,the deformation behavior of as-cast Ti-6Al-4V-0.1B alloy in different temperature and strain rate ranges was studied.The Ti-6Al-4V-0.1B alloy ingot was prepared by vacuum induction skull melting method,and 16 speci⁃mens ofΦ8 mm×13 mm were cut at a distance of 30 mm from the upper surface of the ingot using wire-electrode cutting technology.Subsequently,the alloy was subjected to hot compression test in the temperature range of 850~985℃and the strain rate range of 0.001~1 s^(-1).The true stress-true strain curve was used to study the flow behavior of the alloy.The research results showed that the flow stress of Ti-6Al-4V-0.1B alloy was sensitive to temperature and strain rate,and temperature had a greater influence on flow stress than strain rate.At a given strain rate,the flow stress of Ti-6Al-4V-0.1B alloy decreased with the increase of temperature;while at a given temperature,the flow stress increased with the increase of strain rate.Under the same experimental conditions,the peak stress of Ti-6Al-4V-0.1B alloy was lower than that of Ti-6Al-4V matrix alloy,which was attributed to the refinement effect of trace B on Ti-6Al-4V matrix alloy.The peak strain of all samples appeared near 0.1,which was similar to Ti-6Al-4V alloy,indicating that the addition of a small amount of B did not affect the relationship between the peak stress and strain of the alloy.Perform linear regression on the true stress-true strain curve using the least square method,and the

关 键 词：Ti-6Al-4V-0.1B合金 热压缩 流动应力 TIB 裂纹 

分 类 号：TG146.2[一般工业技术—材料科学与工程]