多尺度层状组织结构对TC21钛合金力学性能的影响  

Effect of the Multiscale Lamellar on Mechanical Properties of TC21 Titanium Alloy

作　　者：谭长生 樊伊朵 李雪静 黄朝文 何佳豪 张国君[1] Tan Changsheng;Fan Yiduo;Li Xuejing;Huang Chaowen;He Jiahao;Zhang Guojun(School of Materials Science and Engineering,Xi’an University of Technology,Xi’an 710048,China;National and Local Joint Engineering Laboratory of High Performance Metallic Structural Materials and Manufacturing Technology,Guizhou University,Guiyang 550025,China)

机构地区：[1]西安理工大学材料科学与工程学院,陕西西安710048 [2]贵州大学高性能金属结构材料与制造技术国家地方联合工程实验室,贵州贵阳550025

出　　处：《稀有金属材料与工程》2021年第12期4410-4417,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(52001253);中国博士后基金(2020M673614XB);陕西省自然科学基金(2020JQ-618);金属材料强度国家重点实验室开放基金(20202211)。

摘　　要：选用典型的高强韧TC21钛合金,利用基于伪调幅分解机制的"Step-quenching"热处理工艺调控和优化多尺度层状组织结构及其力学性能。利用SEM、TEM等研究多尺度层状组织结构的微观组织形貌、断口表面形貌、横截面裂纹扩展形貌等特征。结果表明,等温淬火温度对α相析出行为和合金力学性能有强烈影响。将试样在930℃固溶1 h,分别在0、400、600℃温度范围等温保温2 h后水冷到室温,次生α相的宽度逐渐增加,硬度先增加后稍有降低,在400℃保温的硬度达到最高值;将试样在880、930和960℃固溶1 h,并在400℃等温保温2 h后水冷至室温,分别获得粗片层组织、多尺度层状组织和细片层组织,合金的硬度和强度随固溶温度的升高依次增加。然而,多尺度片层组织表现出优异的抗裂纹扩展能力,其断裂韧度高达104 MPa·m^(1/2),显著高于粗片层组织(67 MPa·m^(1/2))和细片层组织(33 MPa·m^(1/2)),机制分析结果表明这归因于滑移难以穿过相界面、曲折的裂纹扩展路径和裂纹偏转等特性。TC21 titanium alloy with high strength and toughness was selected,and the heat treatment process of“Step-quenching”was used to regulate and optimize the multi-scale lamellar microstructure and its mechanical properties.The microstructure morp hology,fracture morphology and cross-section crack propagation morphology of multi-scale lamellar microstructure were investigated by SEM and TEM.The results show that the isothermal quenching temperature has a strong influence on theαphase precipitation behavior and the mechanical properties of the alloy.The samples were solution treated at 930℃for 1 h,and then step-quenched at temperature of 0℃to 600℃for 2 h,and cooled to room temperature.With the increase of temperature,the width of secondaryαlath phase gradually increases,and the hardness first increases and then decreases slightly,among which the hardness at 400℃being the highest.The samples were solution treated from 880℃to 960℃for 1 h and aged at 400℃for 2 h with water cooling to room temperature.Thus,coarse lamellar,multi-scale lamellar and fine lamellar microstructures were obtained,and the hardness and strength of the alloy increase successively.However,due to its tortuous crack propagation path and crack deflection characteristics,the multi-scale lamellar microstructure shows excellent crack propagation resistance(K_(Q)=104 MPa·m^(1/2)),which is significantly higher than those of the coarse lamellar(K_(Q)=67 MPa·m^(1/2))and the fine lamellar microstructure(K_(Q)=33 MPa·m^(1/2)).

关 键 词：TC21钛合金 等温淬火 多尺度层状组织结构 力学性能 

分 类 号：TG146.23[一般工业技术—材料科学与工程]