深冷处理时间对TC4钛合金微观组织结构及力学性能的影响  

Effect of Cryogenic Treatment Duration on Microstructure and Mechanical Properties of TC4 Dual-Phase Titanium Alloy

作　　者：李晓琛 王世颖 陈智栋 LI Xiaochen;WANG Shiying;CHEN Zhidong(School of Materials Science&Engineering,Changzhou University,Changzhou 213164,China;School of Petrochemical Engineering,Changzhou University,Changzhou 213164,China)

机构地区：[1]常州大学材料科学与工程学院,江苏常州213164 [2]常州大学石油化工学院,江苏常州213164

出　　处：《常州大学学报（自然科学版）》2022年第4期7-13,共7页Journal of Changzhou University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51601020,51574047)。

摘　　要：采用液氮直冷法在-196℃下对TC4双相钛合金进行不同时间的深冷处理,利用金相显微镜对晶粒尺寸进行表征;利用扫描电子显微镜(SEM)对α相和β相体积分数进行表征;利用维氏硬度仪、电子万能试验机分别对硬度和拉伸性能进行表征。通过晶粒尺寸以及α相和β相等组织结构的变化,来分析材料的硬度和拉伸性能的变化原因。实验结果表明:随着深冷时间的延长,材料的晶粒尺寸逐渐下降,β相的体积分数逐渐减少,转变为α相。材料经过12 h的深冷处理后,晶粒得到细化,β相向α相转变,材料在深冷12 h时综合力学性能表现优异;当深冷时间超过12 h后,材料内α相和β相两相体积分数与12 h两相体积分数相比没有明显的变化,并且由于深冷超过12 h的样品在取出到室温后,材料局部回复作用越发明显,整体晶粒尺寸相比12 h时,没有明显的细化,因此,材料的强度和硬度均低于12 h时的强度和硬度。综上所述,深冷12 h为最佳深冷时间,TC4钛合金在液氮中经过12 h的深冷处理可以获得优异的综合力学性能。The TC4 dual-phase titanium alloy was cryogenically treated for different times at -196℃ by liquid nitrogen direct cooling,and the grain size was characterized by metallurgical microscope;the volume fraction of α and β phases was measured by scanning electron microscope(SEM);Vickers hardness tester and electronic universal testing machine were applied to characterize hardness and tensile properties respectively.Through the change of grain size and the structure of α phase and β phase,the changes of material hardness and tensile properties were carefully explained.The experimental results show that with the extension of the cryogenic time,the grain size gradually decreases,and the volume fraction of the β phase gradually decreases by transforming into theαphase.After 12 h cryogenic treatment,the crystal grains are obviously refined,and the majority of β phase is transformed to theαphase.The samples shows superior comprehensive mechanical performance.When the cryogenic time exceeds 12 h,the volume fraction of theαphase and β phase have no obvious change.After taken out to room temperature,the recovery effect of the samples cryogenic treated over 12 h was more obvious,and the mean grain size was not significantly refined compared with that of the samples treated for 12 h.Consequently,the strength and hardness of the sample treated over 12 h were slightly lower than those of the sample treated at 12 h.In conclusion,the superior comprehensive mechanical properties can be obtained after cryogenic treated for 12 h in liquid nitrogen.

关 键 词：深冷处理 TC4双相钛合金 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]