摘要
The microstructures and hot tensile behaviors of ZK30 alloys subjected to single-and multi-pass friction stir processing(FSP)were systematically investigated.Following single-pass FSP(S-FSP),coarse grains underwent refinement to 1−2μm,with a distinct basal texture emerging in the stir zone(SZ).Additionally,second-phase particles were fragmented,dispersed,and partially dissolved.Multi-pass FSP(M-FSP)further enhanced the homogeneity of the microstructure,reduced texture intensity differences,and decreased the fraction of second-phase particles by 50%.Both S-FSP and M-FSP SZs demonstrated superplasticity at strain rates below 1×10^(−3)s^(−1)and at temperatures of 250−350℃.The S-FSP SZ exhibited an elongation of 390%at 250℃and 1×10^(−4)s^(−1),while the M-FSP SZ achieved an elongation of 406%at 350℃and 1×10^(−3)s^(−1).The superplastic deformation of SZ was co-dominated by grain boundary sliding(GBS)and the solute-drag mechanism in S-FSP and mainly by GBS in M-FSP.
系统研究单道次和多道次搅拌摩擦加工(FSP)后ZK30合金的显微组织和热拉伸行为。单道次搅拌摩擦加工(S-FSP)后,搅拌区(SZ)中的粗晶被细化至1~2μm,并呈现显著的基面织构。此外,第二相粒子发生碎裂、分散并部分溶解。多道次搅拌摩擦加工(M-FSP)提高了ZK30合金显微组织的均匀性,降低了搅拌区的织构强度差异,第二相粒子的比例降低了50%。在应变速率低于1×10^(−3)s^(−1)和温度为250~350℃时S-FSP和M-FSP SZ均表现出超塑性。S-FSP SZ在250℃和1×10^(−4)s^(−1)时的断裂伸长率为390%,而M-FSP SZ在350℃和1×10^(−3)s^(−1)时的断裂伸长率为406%。对于S-FSP,SZ的超塑性变形主要由晶界滑移(GBS)和溶质拖曳机制协同作用,而对于M-FSP,GBS为其主要变形机制。
基金
supported by Hebei Natural Science Foundation,China (No.E2020203158)
Hebei Provincial Department of Human Resources and Social Security,China (No.E2020100006)。
