原位自生TiB_(2)/7050铝基复合材料高周疲劳特性  

Study on the high cycle fatigue properties of in-situ TiB_(2)/7050 composite

作　　者：段敏鸽[1] 李晨 李彪[1] 李亚智[1] DUAN Minge;LI Chen;LI Biao;LI Yazhi(School of Aeronautics,Northwestern Polytechnical University,Xi'an 710072,China;National Key Laboratory of Science and Technology on Liquid Rocket Engines,Xi'an Aerospace Propulsion Institute,Xi'an 710100,China)

机构地区：[1]西北工业大学航空学院,西安710072 [2]西安航天动力研究所液体火箭发动机技术重点实验室,西安710100

出　　处：《复合材料学报》2023年第11期6430-6438,共9页Acta Materiae Compositae Sinica

基　　金：国家科技重大专项(J2019-I-0016-0015);中国航空发动机集团产学研合作项目(HFZL2019CXY015)。

摘　　要：原位自生TiB_(2)/Al复合材料是一类新型铝基复合材料,结合了陶瓷材料高硬度、耐高温、耐腐蚀等和铝合金材料良好的韧性和塑性加工特性等的性能特点,具有高比强度、高比刚度、广泛的合金基体选择范围、原材料成本低、制造和热处理工艺多样化等优势。然而,目前原位自生TiB_(2)/Al复合材料的疲劳研究多侧重于微观机制研究,疲劳特性鲜有涉及应力比和缺口敏感性的讨论。以体积分数为3.67vol%的原位自生TiB_(2)颗粒增强7050铝基复合材料(in-situ TiB_(2)/7050-Al)为研究对象,开展了其高周疲劳特性试验研究,并与不含颗粒的7050铝合金进行对比。试验结果表明:在相同的疲劳载荷下,in-situ TiB_(2)/7050-Al的疲劳强度明显大于7050铝合金;应力比为0.1和0.5时,该复合材料的疲劳极限较7050铝合金分别提高了24.59%和13.56%。进行了不同应力集中系数下的疲劳寿命对比,结果表明颗粒引入后一定程度上限制了复合材料基体的塑性变形,提高了其缺口敏感性。尽管如此,in-situ TiB_(2)/7050-Al在存在缺口情况下的疲劳寿命仍高于7050铝合金。in-situ TiB_(2)/7050-Al作为一种新型轻量化结构材料,有望代替传统铝合金,实现结构静强度和疲劳性能的共同提升。In-situ TiB_(2)/Al composite is a new type of aluminum matrix composite,which has the advantages of high specific strength and specific stiffness,good performances on wear resistance,electrical conductivity and thermal conductivity,a variety of matrix alloy candidates,low raw material cost,simple and diversified manufacturing and heat treatment processes.The existing research on the fatigue of in-situ TiB_(2)/Al composites mainly focuses on the strengthening mechanism in micro-scale and the general understanding of its fatigue performance is not sufficient.It is also lack of fatigue test data of in-situ TiB_(2)/Al composite for the engineering use.High cycle fatigue properties of the in-situ TiB_(2) particle reinforced 7050 aluminum alloy composite(in-situ TiB_(2)/7050-Al)with volume fraction of 3.67vol% was experimentally investigated with comparison to 7050-Al,the matrix alloy of the composite.The results reveal that the fatigue strength of the in-situ TiB_(2)/7050-Al is apparently higher than that of 7050-Al.The fatigue limits of in-situ TiB_(2)/7050-Al are improved by 24.59% and 13.56% for stress ratios 0.1 and 0.5 separately,resulting from the increase of fatigue resistance induced by the tiny TiB_(2) particles.The results at different stress concentration levels show that the notch sensitivity of in-situ TiB_(2)/7050-Al is higher than that of 7050-Al,which may attribute to TiB_(2) particles impeding the plastic deformation of the aluminum alloy matrix in the composite.Despite the higher notch sensitivity,the fatigue resistance of the notched composite is still higher than that of the 7050-Al.Therefore,in-situ TiB_(2)/7050-Al is a promising material for lightweight structure application to replace traditional aluminum alloy in certain circumstances and achieve the joint improvement of static strength and fatigue performance.

关 键 词：原位自生颗粒 高周疲劳 颗粒强化 缺口效应 铝基复合材料 

分 类 号：TB331[一般工业技术—材料科学与工程]