耐热高熵多主元合金及其强韧化研究现状

Advances of the Strengthening and Toughening of High-entropy Multi-principal-element Heat-resistant Alloys

航天、航空、船舶等工业的飞速发展对耐热合金提出了更高的要求。传统的耐热合金经长期深入发展,其高温性能已经挖掘至接近极限,亟待开发新的耐热合金体系。近年来提出的多主元高熵合金颠覆了传统固溶体合金的设计理念,显著拓宽了合金设计的成分范围,有望利用这一新的合金设计理念开发出性能更加优异的耐热合金体系。已提出的多种耐热多主元合金体系表现出各自独特的性能特点,也存在各自的不足。其中,体心立方结构的难熔多主元合金具有很高的高温强度,但室温韧性较差;而面心立方结构的多主元合金具有优异的韧塑性,但高温强度较低。针对这些问题,研究人员研究了多种强韧化方法,产生了显著的强韧化效果。本文总结了已有的耐热多主元合金体系,分析了不同合金的微观组织特点和强韧化机理,展望了耐热多主元合金的发展方向,以期为突破新型耐热合金体系开发的学术研究和工程应用提供一定的参考。

Heat-resistant alloys are unique high-temperature materials widely used in the aerospace and shipbuilding industries.However,operating temperatures are now reaching limits posed by the melting temperatures of these materials.Since 2004,a new alloy design philosophy—high-entropy alloy(HEAs)or multi-principle-element alloys(MPEAs)were proposed,which have attracted significant attention due to their excellent mechanical properties,including high strength and high ductility.Due to their superior mechanical performance,HEAs are promising to be deve-loped on heat-resistant alloys.Among them,refractory HEAs with body-centered cubic(BCC)structure exhibit high high-temperature strength but poor room-temperature plasticity,while HEAs with face-centered cubic(FCC)structure show great ductility but low high-temperature strength.A variety of strengthening and toughening methods were conducted for FCC and BCC HEAs,respectively.The present work summarizes the research progress of heat-resistant HEAs.The microstructure evolution and mechanical properties at high temperatures are briefly reviewed.Finally,the future perspective of heat-resistant HEAs is prospected.