Alloy design by dislocation engineering

作     者：M.X.Huang B.B.He 

作者机构：Department of Mechanical Engineering The University of Hong Kong 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2018年第34卷第3期

页      面：417-420页

核心收录：

学科分类：08[工学] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：the support from Research Grants Council of Hong Kong (Grants No. 17203014, HKU712713E and 17255016) the National Natural Science Foundation of China (Grant No. U1560204) 

主　　题：Alioy design Dislocation engineering D＆P steel Q＆P steel TRIP Warm rolling 

摘      要：Ultra-high strength alloys with good ductility are ideal materials for lightweight structural application in various industries. However, improving the strength of alloys frequently results in a reduction in ductility, which is known as the strength-ductility trade-off in metallic materials. Current alloy design strategies for improving the ductility of ultra-high strength alloys mainly focus on the selection of alloy composition （atomic length scale） or manipulating ultra-fine and nano-grained microstructure （grain length scale）. The intermediate length scale between atomic and grain scales is the dislocation length scale. A new alloy design concept based on such dislocation length scale, namely dislocation engineering, is illustrated in the present work. This dislocation engineering concept has been successfully substantiated by the design and fabrication of a deformed and partitioned （D＆P） steel with a yield strength of 2,2 GPa and an uniform elongation of 16%. In this D＆P steel, high dislocation density can not only increase strength but also improve ductility. High dislocation density is mainly responsible for the improved yield strength through dislocation forest hardening, whilst the improved ductility is achieved by the glide of intensive mobile dislocations and well-controlled transformation-induced plasticity （TRIP） effect, both of which are governed by the high dislocation density resulting from warm rolling and martensitic transformation during cold rolling. In addition, the present work proposes for the first time to apply such dislocation engineering concept to the quenching and partitioning （Q＆P） steel by incorporating a warm rolling process prior to the quenching step, with an aim to improve simultaneously the strength and ductility of the Q＆P steel. It is believed that dislocation engineering provides a new promising alloy design strategy for producing novel strong and ductile alloys.