热处理对Ti-45.5Al-4Cr-2.5Nb合金组织和性能的影响  

Effect of the Heat Treatment on the Microstructure and Properties ofTi-45.5Al-4Cr-2.5Nb Alloy

作　　者：王国田[1] 龙泽堃 周西来 王思元 WANG Guotian;LONG Zekun;ZHOU Xilai;WANG Siyuan(College of Automobile and Transportation Engineering,Heilongjiang Institute of Technology,Harbin 150050,China;School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]黑龙江工程学院汽车与交通工程学院,哈尔滨150050 [2]哈尔滨工业大学材料科学与工程学院,哈尔滨150001

出　　处：《材料导报》2024年第S01期461-465,共5页Materials Reports

基　　金：国家自然科学基金(52171112);省属本科高校基本科研项目(2023GJ07);省领军人才梯队培育计划(2020LJ04)。

摘　　要：钛铝合金因其高比强度、高比弹性模量、良好的高温抗氧化性和优良的高温性能,已成为新一代高温材料的代表之一。然而,其较低的室温脆性和断裂韧性限制了其工程应用。本实验采用水冷铜坩埚真空感应熔炼炉(ISM)制备TiAl合金,在脉冲电流作用定向凝固后,采用OM、SEM以及万能材料试验机研究了热处理对电场作用下定向凝固Ti-45.5Al-4Cr-2.5Nb合金组织和性能的影响。结果表明,热处理前后TiAl基合金组织的晶粒取向、排列基本一致,高温热处理使晶粒尺寸增大,晶粒平均偏离角和一次枝晶间距都有所增大,重结晶晶粒内由γ/B2片层变为γ/α_(2)全片层组织。高温热处理使B2相熔解,含量大幅减少,重新结晶组织转变为全片层组织,使TiAl合金抗拉强度、延伸率显著提高,相较于原始母合金,抗拉强度提高了92.7%,延伸率提高了189.3%。TiAl-based alloys have become one of the representatives of the new generation of high temperature materials because of their high specific strength,high specific elasticmodulus,good high temperature oxidation resistance and excellent high temperature properties.However,lower room temperature brittleness and fracture toughness limit its engineering application.In this work,TiAl alloy was prepared by water-cooled copper crucible vacuum induction smelting furnace(ISM).After the directional solidification of pulsed current,the influence of heat treatment on the structure and properties of Ti-45.5Al-4Cr-2.5Nb alloy was studied by OM,SEM and universal material testing machine.The results show that the grain orientation and arrangement of TiAl base alloy tissue were basically the same before and after heat treatment.The high temperature heat treatment increased the grain size,the average deviation Angle and the spacing of the primary dendrite increased,and the recrystallized grain changed fromγ/B2 toγ/α_(2).The high temperature heat treatment makes B2 phase melt,the content is greatly reduced,and the recrystallized tissue is transformed into the whole sheet tissue,making the tensile strength and elongation rate of TiAl alloy significantly improved.Compared with the original parent alloy,the tensile strength is increased by 92.7%,and the elongation rate is increased by 189.3%.

关 键 词：TIAL合金 定向凝固 热处理 显微组织 力学性能 

分 类 号：TG156.95[金属学及工艺—热处理]