城轨列车制动盘SiC_(p)/A356复合材料热疲劳裂纹扩展机理  

Thermal fatigue crack propagation mechanism of SiC_(p)/A356 composites for urban rail train brake disc

作　　者：杨智勇[1] 臧家俊 方丹琳 李翔 李志强[1] 李卫京[1] YANG Zhiyong;ZANG Jiajun;FANG Danlin;LI Xiang;LI Zhiqiang;LI Weijing(School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong University,Beijing 100044,China;School of Technology,Beijing Forestry University,Beijing 100083,China;Metal&Chemistry Research Institute,China Academic of Railway Sciences,Beijing 100081,China)

机构地区：[1]北京交通大学机械与电子控制工程学院,北京100044 [2]北京林业大学工学院,北京100083 [3]中国铁道科学研究院金属及化学研究所,北京100081

出　　处：《材料工程》2022年第7期165-175,共11页Journal of Materials Engineering

基　　金：中央高校基本科研业务费专项资金(2021YJS146);中央高校基本科研重点基金(2020JBZ113)。

摘　　要：为研究制动盘服役温度载荷及材料微结构对SiC_(p)/A356复合材料热疲劳裂纹扩展行为的影响,明确其热疲劳裂纹扩展微观机理,开展SiC_(p)/A356复合材料热疲劳裂纹扩展实验。结果表明:裂纹扩展过程包括由SiC颗粒偏转作用和二次裂纹释放扩展驱动力导致的缓慢扩展阶段和主裂纹与裂纹扩展前端微损伤连接的快速扩展阶段;加热温度较低时,裂纹扩展的“台阶状”特征明显,整体扩展速率较低,裂纹宽度较小,裂纹扩展方式为颗粒断裂、轻量基体撕裂和沿界面开裂;加热温度较高时,“斜直线跃升”阶段更为明显,裂纹宽度较大且扩展速率较高,裂纹扩展以颗粒脱落以及大幅度基体撕裂为主;主裂纹总是通过选择沿SiC颗粒群或者直接穿过α-Al基体以阻力较小的方式向前扩展,Si相承载时极易发生断裂,成为裂纹扩展源,同时裂纹扩展前端的微损伤对其扩展具有引导作用。In order to study the influence of the service temperature load and material microstructure on the thermal fatigue crack growth behavior of SiC_(p)/A356 composites,and to clarify the microscopic mechanism of thermal fatigue crack growth,the thermal fatigue crack growth test of SiC_(p)/A356 composites was carried out.The results show that the crack growth process includes the slow growth stage caused by the deflection of SiC particles and the release of the driving force of the secondary crack growth,and the rapid growth stage where the main crack is connected with the micro-damage front end of the crack growth.When the heating temperature is low,the“step-like”feature of crack growth is obvious,the overall growth rate is slower,and the crack width is smaller,the crack propagation methods are particle fracture,light-mass matrix tearing and cracking along the interface.When the heating temperature is higher,the“oblique straight-line jump”stage is more obvious,the crack width is large and the growth rate is high,the crack growth is dominated by particle shedding and large-scale matrix tearing.Main crack always propagates forward with less resistance by choosing to follow the SiC particle group or directly pass through theα-Al matrix,when Si phase is loaded,it is easy to fracture and become the source of crack propagation.At the same time,the micro-damage at the front end of the crack propagation has a guiding effect on the crack propagation.

关 键 词：SiC_(p)/A356复合材料 服役温度载荷 热疲劳 裂纹扩展微观机理 

分 类 号：TG146.2[一般工业技术—材料科学与工程]