Influence of Cr element on impact fracture process of ductile Ni-resistant alloyed iron at low temperature

作     者：Ke Jiang Ying-dong Qu Jun-hua You Rong-de Li Qing-chun Xiang Yu-xiong Zhou 

作者机构：School of Materials Science and Engineering Shenyang University of Technology 

出 版 物：《China Foundry》 (中国铸造（英文版）)

年 卷 期：2016年第13卷第1期

页      面：42-46页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China(No.51274142) the Natural Science Foundation of Liaoning Province(No.2014028015) the Science&Technology Project of Shenyang City(No.F15-199-1-15) 

主　　题：Ni-resistant alloyed iron carbide impact fracture low temperature Cr addition 

摘      要：In this study, in order to investigate the influence of Cr element on the impact fracture process of ductile Ni-resistant alloyed iron at low temperature, different contents of Cr element were added to ductile Ni-resistant(DNR) austenitic alloyed iron. The experimental results show that Cr addition can increase the hardness of the DNR alloyed iron, but it has an destructive effect on low-temperature impact properties. Through the analysis of the dynamic load and absorbed energy of samples with different Cr contents in the impact fracture process, and the comparison of the impact fracture process at room and low temperatures, it reveals that Cr addition into the DNR alloyed iron can facilitate the formation of the carbide mixture in Mn23C6 and Cr23C6 with homogeneous and discontinuous distribution. Meanwhile, Cr addition also can improve the the maximum dynamic load and crack initiation energy at low temperature, but has no obvious effect on the yield behavior of the DNR alloyed iron in the impact fracture process. Compared with the impact crack propagation process at room temperature, the metastable propagation energy at low temperature declines significantly with an increase in Cr content. This is because the micro-cracks that caused by the carbides weaken the matrix, resulting in the decline of impact crack propagation resistance. The fracture analysis results also show that the impact fracture mechanism gradually transforms from ductile to brittle with an increase in Cr content at low temperature. It explains that too much Cr addition can lead to brittle fracture even though the austenitic matrix has a good toughness at low temperature.