CADI冲击疲劳失效机理研究  

Study on Failure Mechanism in Impact Fatigue of CADI

作　　者：杨鹏辉 符寒光[3] 徐建林[1,2] YANG Penghui;FU Hanguang;XU Jianlin(State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,Lanzhou University of Technology,Lanzhou 730050;School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050;School of Materials Science and Engineering,Beijing University of Technology,Beijing 100124)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050 [2]兰州理工大学材料科学与工程学院,兰州730050 [3]北京工业大学材料科学与工程学院,北京100124

出　　处：《机械工程学报》2023年第22期312-321,共10页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51775006);甘肃省科技计划(23JRRA810);甘肃省高校青年博士支持(2023QB-035)资助项目。

摘　　要：含碳化物等温淬火球墨铸铁(Carbidic austempered ductile iron,CADI)因其优良力学性能已成为球磨机磨球的重要材料之一,然而由于CADI组相复杂,导致目前研究无法搞清楚石墨球、铁素体、残余奥氏体和碳化物如何影响冲击疲劳下CADI的失效。使用改造后的MLD-10试验机分析奥氏体化温度、等温淬火温度及冲击载荷对CADI冲击疲劳裂纹影响。通过自制试验机制备冲击疲劳试样,研究冲击疲劳后试样表面和横截面的变化规律,并揭示CADI冲击疲劳失效机理,即石墨球变形和碳化物断裂产生了大量冲击疲劳裂纹,导致CADI沿晶断裂。细小且分布均匀的石墨球和碳化物更有利于提高CADI抗冲击疲劳性,超高温预热处理+等温淬火的工艺获得的含沉淀颗粒和超细针状铁素体的高韧性CADI不易在冲击疲劳过程中断裂,具有广阔的应用前景。Carbidic austempered ductile iron(CADI)is one of the important materials for grinding balls in ball mill due to its excellent mechanical properties.However,the failure mechanism of CADI under impact fatigue is lack of research because the complex phase composition(such as graphite nodules,ferrite,retained austenite and carbides)can affect the performance.The effects of austenitizing temperature,austempering temperature and impact load on CADI impact fatigue cracks are analysed by the modified MLD-10 tester.The sample for impact fatigue is prepared by a self-made tester.The changes of the sample surface and cross section after impact fatigue are studied,and the failure mechanism of CADI impact fatigue is revealed.That is,a large number of impact fatigue cracks are produced due to the deformation of graphite nodules and the fracture of carbides,resulting in the intergranular fracture.Fine graphite balls and carbides with uniform distribution are more conducive to improving the impact fatigue resistance.The high toughness CADI obtained by the super-high temperature pretreatment and austempering treatment is not easy to fracture during the impact fatigue process,which shows that it has broad application prospects.

关 键 词：CADI 冲击疲劳 组织 失效机理 

分 类 号：TG255[金属学及工艺—铸造]