合金化元素Ti对Laves相Cr_2Nb力学性能及耐蚀性的影响  

Effects of Ti Addition on the Mechanical Properties and Corrosion Resistance of the Cr_2Nb Laves Phase

作　　者：张婷[1] 李双明[1] 李克伟[1] 薛云龙[1] 钟宏[1] 傅恒志[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《稀有金属材料与工程》2015年第3期697-702,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金资助项目(51074127;51104120);教育部留学回国人员科研启动基金资助项目

摘　　要：采用真空非自耗电弧熔炼工艺制备了Cr2Nb-XTi(X=5,10,15,at%)合金,利用光学显微镜(OM),X射线衍射(XRD)仪,扫描电镜(SEM)对电弧熔炼态铸锭的组织进行了研究,探讨了合金化元素Ti的含量对Laves相Cr2Nb力学性能及耐蚀性的影响。结果表明:3种成分的电弧熔炼态合金凝固组织主要由C15-Cr2(Nb,Ti)相和六方的β-(Ti,Nb)以及体心立方结构的β-(Nb,Ti)相组成。在5Ti和10Ti合金冷速较小的铸锭上部凝固组织中出现了亚稳相C14-Cr2(Nb,Ti)。通过对合金力学性能研究表明,随合金化元素Ti含量的增加,Laves相Cr2Nb合金的显微硬度逐渐降低,断裂韧性增大,当Ti含量达到15at%时,合金的断裂韧性达到了3.1 MPa·m1/2,比单相Laves相Cr2Nb提高1倍。另外,对腐蚀性能的测试表明,Ti含量增加材料腐蚀性能下降,但15Ti合金仍表现出良好的耐蚀性。The ternary alloys of Cr2Nb-XTi（X=5, 10, 15, at%） were prepared by vacuum non-consumable arc melting. The solidification microstructures of arc-melted alloy were investigated using optical microscope（OM）, X-ray diffraction（XRD） as well as scanning electron microscope（SEM）, and the effects of Ti addition on the mechanical properties and corrosion resistance of Laves- phase Cr2 Nb were also studied. The results show that the solidified microstructures of these ternary alloys are mainly composed of C15-Cr2（Nb,Ti）, β-（Ti,Nb） andβ-（Nb,Ti）. A metastable phase C14-Cr2（Nb,Ti） is observed only in the top part of the arc-melted ingots of Cr2Nb-5Ti and Cr2Nb-10 Ti alloys at low cooling rate. Meanwhile, with the increase in Ti content, the microhardness of Cr2Nb-XTi alloy decreases gradually and the alloy fracture toughness increases continuously. As the Ti content reaches 15at%, the fracture toughness of the alloy Cr2Nb-15 Ti could attain 3.1MPa.m1/2, twice of that of the single-phase Cr2 Nb. In addition, as the Ti content increases, the corrosion performance of the alloy Cr2Nb-XTi declines, but the alloy Cr2Nb-15 Ti still exhibits well corrosion resistance.

关 键 词：真空非自耗电弧熔炼 Cr-Nb-Ti三元合金 微观组织 力学性能 耐蚀性 

分 类 号：TG144[一般工业技术—材料科学与工程]