激光沉积Ti-6Al-2Zr-Mo-V钛合金高周疲劳性能  

HCF Properties of Laser Deposited Ti-6Al-2Zr-Mo-V Alloy

作　　者：贺瑞军[1] 王华明[1] 

机构地区：[1]北京航空航天大学材料科学与工程学院,北京100191

出　　处：《航空学报》2010年第7期1488-1493,共6页Acta Aeronautica et Astronautica Sinica

基　　金：国家自然科学基金(50625413);国家"973"计划(2006CB605206-2)

摘　　要：疲劳失效是钛合金工业应用中最重要的失效方式,疲劳强度是钛合金应用的关键性指标。为了研究激光沉积Ti-6Al-2Zr-Mo-V钛合金的疲劳性能和行为,在625MPa到900MPa不同应力水平下进行了室温高周疲劳(HCF)测试(应力比R=0.1,加载频率f=120～130Hz),完成了疲劳断口表面分析。研究了气孔存在及分布对激光沉积Ti-6Al-2Zr-Mo-V钛合金疲劳性能的影响。激光沉积钛合金具有细小α/β片层组织。分析结果显示,虽然疲劳源区有气孔存在,激光沉积Ti-6Al-2Zr-Mo-V钛合金仍然具有优异的疲劳性能。取向丰富细小的α/β片层组织能有效减小疲劳源区滑移长度。分析结果还表明,应力水平对疲劳行为有一定影响。Fatigue failure is the most important failure mode in industrial applications of titanium alloys while fatigue strength is the critical mechanical property.First,the fatigue properties of laser deposited Ti-6Al-2Zr-Mo-V alloy are studied.High-cycle fatigue （HCF） test is conducted at room temperature at several different stress levels ranging from 625 MPa to 900 MPa,with a load ratio of 0.1 and a frequency of 120-130 Hz.Fatigue fracture surface is analyzed by scanning electron microscope （SEM）.Then,the influence of micropores and their distribution on fatigue properties of laser deposited Ti-6Al-2Zr-Mo-V alloy is investigated.Fine α/β lamellar structure is obtained in laser deposited Ti-6Al-2Zr-Mo-V alloy.The examination results of high-cycle fatigue tests indicate that although micropores exist in the fatigue crack initiation regions,laser deposited Ti-6Al-2Zr-Mo-V alloy still has excellent fatigue properties.The fine α/β lamellar structure can effectively lend to the reduction of slip length in the crack initiation regions.Furthermore,the results also show that there is certain influence of stress level on fatigue behavior.

关 键 词：钛合金 高周疲劳 疲劳强度 激光沉积 显微组织 

分 类 号：V252[一般工业技术—材料科学与工程] TG146.23[航空宇航科学与技术—航空宇航制造工程]