WC_p/钢基表面复合材料热疲劳裂纹萌生及扩展机理  

Initiation and propagation mechanism of thermal fatigue crack in WC_p/steel surface composites

作　　者：黄汝清[1,2] 隋育栋[1,2] 蒋业华[1,2] 李祖来[1,2] 山泉[1,2] 

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]云南省先进成形制造工程技术研究中心,云南昆明650093

出　　处：《材料热处理学报》2013年第3期40-43,共4页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(50871048);云南省应用基金(2008E036M)

摘　　要：为了对经受热疲劳的表面复合材料的设计提供理论依据,采用热震试验方法对通过真空实型铸渗(V-EPC)方法制备的WC/钢基表面复合材料的热疲劳性能进行了研究,重点讨论了表面复合材料热疲劳裂纹萌生及扩展的影响因素。结果表明,在本实验条件下Ni6025WC体积分数为15%时的热疲劳性能较5%时得到较大改善。表面复合材料的热疲劳裂纹的萌生和扩展的影响因素有以下几个方面:WC颗粒本身微观质量和热导率、复合层与基材中主要元素以及WC颗粒的平均热膨胀系数、复合层中WC颗粒之间的间距、由热震而产生的界面交变循环应力等。通过改善以上影响因素可以提高复合材料的热疲劳性能。Thermal fatigue performance of WC ＋ Ni6025WC/steel matrix surface composites obtained by the V-EPC infiltrating process and mechanism of thermal fatigue crack initiation and propagation in the composites were studied by thermal shock test. The results show that the composites with the addition of 15vo1% Ni6025WC powder exhibits a good thermal fatigue performance, and only some uncontinues fine cracks are observed in the composites after thermal shock test for 60 cycles. The factors including quality, thermal conductivity and distribution of the ceramic carbide particle, thermal stress and alternating at the interface between WC particles and matrix produced during thermal shock test influence the initiation and propagation of thermal stress fatigue crack in the surface composites. The thermal fatigue performance of the composites can be improved by proper design of composition and mierostrueture.

关 键 词：表面复合材料 热应力 界面交变循环应力 热疲劳性能 

分 类 号：TB331[一般工业技术—材料科学与工程]