材料期刊网

材料的强化通常是在材料内部引入各种缺陷以阻碍位错运动来实现, 如固溶强化、弥散强化、细晶强化和应变强化等,但这些传统的强化途径无可避免地会影响材料的塑性形变能力, 导致塑性和韧性的降低. 利用纳米尺度孪晶界面实现材料强化可避免上述缺点. 本文对纳米孪晶强化原理和纳米孪晶金属研究进展进行了简要综述, 分别讨论了纳米孪晶变形机制、纳米孪晶金属的部分力学行为(如强度、塑性、应变速率敏感性和加工硬化等)和物理性能(如导电性), 以及纳米孪晶金属的制备技术等相关问题.

Strengthening materials is a central objective of materials research. Traditional approaches to strengthen materials, including solid solution strengthening, second phase strengthening, grain refinement strengthening, dispersion strengthening and work hardening strengthening etc., aim at creation of internal defects and boundaries so as to obstruct the motion of dislocations. Such strategies for strengthening invariably compromise the ductility and electrical conductivity of the material. By reviewing recent advances in our understanding of nanostructured metals and alloys, we propose a novel approach to optimize the strength, ductility and the electrical conductivity of materials by means of coherent twin boundaries at nano-meter scale. We assess current understanding of strengthening mechanism of twin boundaries (instead of incoherent boundaries as conventionally used). Additionally, some mechanical properties (such as strength, ductility, strain rate sensitivity, work hardening) and the physical properties (electrical conductivity and electrical migration) as well as the relative preparation techniques of the metallic materials with nano-scale twins will be reviewed in this paper.