预时效处理对亚稳态β钛合金TB18组织性能的影响  

Effect of pre-aging treatment on microstructure and mechanicalproperties of metastableβtitanium alloy TB18

作　　者：李波 向伟 张枫 秦锋英 袁武华[3] Li Bo;Xiang Wei;Zhang Feng;Qin Fengying;Yuan Wuhua(AVIC The First Aircraft Institute,Xi'an Shaanxi 710089,China;China National Erzhong Group Deyang Wanhang Die Forging Co.,Ltd.,Deyang Sichuan 618000,China;School of Materials Science and Engineering,Hunan University,Changsha Hunan 410082,China)

机构地区：[1]航空工业第一飞机设计研究院,陕西西安710089 [2]中国第二重型机械集团德阳万航模锻有限责任公司,四川德阳618000 [3]湖南大学材料科学与工程学院,湖南长沙410082

出　　处：《金属热处理》2024年第5期106-111,共6页Heat Treatment of Metals

摘　　要：研究了高强亚稳态β钛合金TB18在不同热处理后的显微组织与力学性能的变化规律。结果表明,固溶后的TB18合金直接在525℃下时效4 h时,β基体中仍保留较多的无析出区(PFZs),此时合金的抗拉强度为1309 MPa,屈服强度为1227 MPa,伸长率为6.6%;若固溶后先进行300℃×2 h的预时效处理再进行时效,TB18合金的显微组织和力学性能并未发生明显的变化;而当预时效的温度提高至400℃时,时效后的显微组织将不再存在大面积的无析出区,并同时提高了合金的强度与塑性,其中抗拉强度、屈服强度和伸长率分别为1355 MPa、1278 MPa和7.0%,表现出更好的强度-塑性匹配;此外,所有拉伸试样的断裂模式均为混合断裂,但固溶+400℃预时效+时效试样断面上的解理特征更少,韧性断裂的比重更大。Relationships of microstructure and mechanical properties of high-strength metastableβtitanium alloy TB18 after different heat treatments were investigated.The results show that many precipitation-free zones(PFZs)still retains in theβmatrix of the TB18 alloy after solution treatment and aging at 525℃for 4 h,where the alloy has an ultimate tensile strength of 1309 MPa,a yield strength of 1227 MPa,and an elongation of 6.6%.When the TB18 alloy is pre-aged at 300℃for 2 h and aged,the microstructure and mechanical properties are not changed significantly.While the pre-aging temperature is increased to 400℃,there are no longer significant PFZs distributed in the microstructure after aging,and the strength and plasticity of the alloy are significantly increased,where the tensile strength,yield strength,and elongation are 1355 MPa,1278 MPa,and 7.0%respectively,showing a better strength-plasticity matching.In addition,all the tensile specimens are fractured in a mixed mode,but the specimens after solution,pre-aging at 400℃and aging have fewer deconstructive features on the section and a greater proportion of ductile fracture.

关 键 词：Β钛合金 预时效 显微组织 力学性能 断裂模式 

分 类 号：TG156.1[金属学及工艺—热处理] TG166.5[金属学及工艺—金属学]