原位自生TiB_(2)/7050复合材料的高周疲劳断裂机制  

High Cycle Fatigue Fracture Mechanism of In-situ TiB_(2)/7050 Composite

作　　者：罗贤[1] 朱金瑶 王泓[1] 乙晓伟[1] 冉刚 胡锐[1] LUO Xian;ZHU Jin-yao;WANG Hong;YI Xiao-wei;RAN Gang;HU Rui(State Key Lab of Solidification Processing,Northwestern Polytechnical University,Xi’an 710027,China)

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《失效分析与预防》2022年第5期286-292,共7页Failure Analysis and Prevention

基　　金：民用飞机专项科研项目(MJ-2016-D-22)。

摘　　要：TiB_(2)/7050铝基复合材料在航空发动机等领域具有重要的应用前景。本文研究了TiB_(2)颗粒质量分数为4%的原位自生7050铝基复合材料在T6热处理状态下的室温高周疲劳性能,利用扫描电子显微镜对复合材料的疲劳断裂机制进行分析。结果表明:在应力比R=−1、指定寿命为3×107周次时,TiB_(2)/7050铝基复合材料的疲劳强度为211.9 MPa,高于7050铝合金的疲劳强度;疲劳裂纹萌生源主要分布在近样品表面的夹杂、大尺寸的TiB_(2)颗粒及显微孔洞等区域;疲劳裂纹的扩展在遇到TiB_(2)颗粒带时,疲劳条带的宽度会明显减小,即TiB_(2)颗粒提高了复合材料的抗疲劳裂纹扩展能力,使得复合材料具有高的疲劳寿命。TiB_(2)/7050 aluminum matrix composites have important application prospects in aeroengine and other fields.The room-temperature high cycle fatigue performance of in-situ 7050 aluminum matrix composites with 4wt.%TiB_(2) particle at T6 state was studied in this work,and the fatigue fracture mechanism of the composites was analyzed by SEM.The results show that when the stress ratio R is−1 and the specified life is 3×107 cycles,the fatigue strength of TiB_(2)/7050 composite is 211.92 MPa,which is higher than that of 7050 Al alloy.The macroscopic morphology of the fatigue fracture includes fatigue propagation source area,fatigue area and final rupture regions.The fatigue crack initiation sources are mainly in the areas of inclusions,large-size TiB_(2) particles and microscopic pores close to the sample surface.When the fatigue crack expansion encounters the TiB_(2) particle band,the width of the fatigue striation significantly reduces,i.e.the TiB_(2) particles improve the fatigue crack expansion resistance of the composite,enabling the composite to have a high fatigue life.

关 键 词：TiB_(2)/7050铝基复合材料 高周疲劳性能 疲劳寿命 疲劳断裂机制 

分 类 号：V258[一般工业技术—材料科学与工程] TB333[航空宇航科学与技术—航空宇航制造工程]