Abstract

In this work, multi-pass friction stir processing (FSP) was successfully applied to AA6061 to reinforce SiC nanoparticles producing defect-free processes. It can be inferred that Nano SiC particles were fragmented totally and uniformly distributed in sixth pass FSP. Agglomeration of SiC particles decreases with increases in the number of FSP pass. In the first pass, the SiC powder with lower formability than the base metal was concentrated inside the groove, so their flow was difficult, and most of them remained at the center of the SZ. The amount of SiC in the surface composite was further decimated after the second pass FSP cycle. At the same time, a progressive and substantial fragmentation of SiC particles ensues after the fourth and sixth passes, respectively, due to improving material mixing and dispersion. The tensile strength of AA6061 exhibited 275.7 MPa, and a percentage strain of 10.9. After implementing multi-pass FSP with nanoparticles of SiC on the AA6061, the tensile properties were enhanced simultaneously as the FSP pass increases. The tensile strength of one pass, two passes, four passes, and six passes was observed as 291.8, 307.5, 330.5, and 348 MPa, respectively, caused by strain-free fine grains during dynamic recrystallization mechanism. In contrast, Vickers’s hardness value along the centerline (stir zone) was observed as 101, 119, 125, and 134 HV with 1, 2, 4, and 6 FSP pass, respectively.

摘要

在这项工作中，多道次摩擦搅拌处理 (FSP) 成功应用于 AA6061，以增强 SiC 纳米颗粒，从而产生无缺陷的工艺。可以推断，纳米SiC颗粒在第六遍FSP中完全破碎且均匀分布。SiC颗粒的团聚随着FSP道次的增加而减少。在第一道次中，成形性低于母材的 SiC 粉末集中在槽内，流动困难，大部分留在 SZ 的中心。在第二次 FSP 循环后，表面复合材料中的 SiC 量进一步减少。同时，由于改进了材料混合和分散，在第四次和第六次通过后，SiC 颗粒分别出现了逐渐和大量的碎裂。AA6061 的抗拉强度为 275.7 MPa，应变百分比为 10.9。在 AA6061 上使用 SiC 纳米颗粒实施多道次 FSP 后，随着 FSP 道次的增加，拉伸性能同时得到增强。1道次、2道次、4道次和6道次的抗拉强度分别为291.8、307.5、330.5和348 MPa，由动态再结晶机制中的无应变细晶粒引起。相比之下，沿中心线（搅拌区）的维氏硬度值分别为 101、119、125 和 134 HV，分别通过 1、2、4 和 6 FSP。两道次、四道次和六道次的压力分别为 291.8、307.5、330.5 和 348 MPa，由动态再结晶机制中的无应变细晶粒引起。相比之下，沿中心线（搅拌区）的维氏硬度值分别为 101、119、125 和 134 HV，分别通过 1、2、4 和 6 FSP。两道次、四道次和六道次的压力分别为 291.8、307.5、330.5 和 348 MPa，由动态再结晶机制中的无应变细晶粒引起。相比之下，沿中心线（搅拌区）的维氏硬度值分别为 101、119、125 和 134 HV，分别通过 1、2、4 和 6 FSP。