热暴露对Ti55合金显微组织及力学性能的影响  

Effect of thermal exposure on microstructure and mechanical properties of Ti55 alloy

作　　者：宋体杰 王长宇[1] 王珏[1] 于妍妍 卢增威 金冬岩 Song Tijie;Wang Changyu;Wang Jue;Yu Yanyan;Lu Zengwei;Jin Dongyan(Shenyang Aircraft Corporation,Shenyang Liaoning 110850,China)

机构地区：[1]沈阳飞机工业(集团)有限公司,辽宁沈阳110850

出　　处：《金属热处理》2024年第1期15-21,共7页Heat Treatment of Metals

基　　金：国家科技重大专项(J2009-VI-0003-0116)。

摘　　要：研究了400~800℃热暴露对锻造变形态Ti55合金显微组织和力学性能的影响,并对其高温疲劳断口的显微形貌特征进行分析。结果表明,550℃以下长时间热暴露时屈服强度和抗拉强度基本保持稳定,而伸长率则随着热暴露温度的升高而下降。800℃以下热暴露不改变Ti55合金的显微组织类型,但热暴露温度升高会使Ti55合金中的β相在α相束集交接处发生局部粗化现象。热暴露温度高于550℃以上时,Si明显偏聚于晶界区域,最大浓度可达1%。随着热暴露温度的升高,Ti55合金的高温疲劳断口特征由穿晶韧性向沿晶脆性转变。Effect of thermal exposure at 400-800℃on the microstructure and mechanical properties of forged Ti55 alloy was studied.Meanwhile,the fatigue fracture micro morphology characteristics at elevated temperature were analyzed.The results show that the yield strength and tensile strength are basically stable under long-term thermal exposure below 550℃,while the elongation decreases with the increase of exposure temperature.Thermal exposure below 800℃does not change the microstructure type of the Ti55 alloy,but with the increase of thermal exposure temperature,theβphase coarsens locally at theαintersection of phase bundles.When exposed above 550℃,Si is obviously concentrated in the grain boundary region,and the maximum concentration is up to 1%.With the increase of thermal exposure temperature,the characteristics of high-temperature fatigue fracture of the Ti55 alloy change from transgranular toughness to intergranular brittleness.

关 键 词：Ti55合金 热暴露 显微组织 力学性能 电子探针 疲劳断口 

分 类 号：TG156.1[金属学及工艺—热处理]