文章信息/Info

Title:

Friction Stir Processing on Fusion Welding Area of 7075 Aluminum Alloy

文章編號:

1674-3962(2023)02-0174-07

作者:

張云龍; 李若琳; 朱彬; 程亮

（江蘇理工學院材料工程學院，江蘇 常州 213001）

Author(s):

ZHANG Yunlong;  LI Ruolin;  ZHU Bin;  CHENG Liang

（School of Materials Engineering, Jiangsu University of Technology, Changzhou 213001, China）

關鍵詞:

7075; 鋁合金; TIG焊; 攪拌摩擦加工; 力學性能

Keywords:

7075;  aluminum alloy;  TIG welding;  friction stir processing;  mechanical properties

分類號:

TG453.9

DOI:

10.7502/j.issn.1674-3962.202209002

文獻標志碼:

A

摘要:

7系超硬鋁合金廣泛應用于航空航天以及汽車等領域，鎢極惰性氣體保護（tungsten inert-gas，TIG）電弧焊可用于構件的修復，但熔焊缺陷以及專用絲材的缺乏使得熔覆層的強度不足。采用ER5356鋁合金焊絲對7075-T6合金進行熔覆修補，并對TIG熔覆層進行攪拌摩擦加工（friction stir processing, FSP），以期改進熔覆層力學性能。固定TIG焊工藝參數和攪拌頭行進速度，研究了攪拌頭轉速對熔覆層組織、力學性能以及斷裂行為的影響，結果表明：TIG熔覆區由粗大的樹枝晶組成，FSP消除了熔覆區的宏觀缺陷，顯著細化晶粒并減小了攪拌區與母材的成分差異。TIG熔覆試樣拉伸斷口位于硬度和強度最低的熔覆區中心。FSP顯著提高了熔覆層的硬度和強度，拉伸斷口位于前進側的熱機械影響區。隨轉速增大，攪拌區平均晶粒尺寸降低，熱機械影響區和攪拌區的強度提高而塑性降低。

Abstract:

7 series duralumin alloys are widely used in aerospace and automotive fields. Tungsten inert gas (TIG) welding can be used to repair components, but the welding defects and the lack of special wire make the strength of the welding layer insufficient. In this paper, ER5356 welding wire was used to 7075-T6 alloy fusion welding, and friction stir processing (FSP) was carried out on TIG welding layer to improve the performance. The effect of rotation speed on the microstructure, mechanical properties and fracture behaviors of the welding layer was studied, with the certain TIG welding processing parameters and traveling speed. The results show that the TIG welding zone (WZ) is composed of coarse dendrites, and FSP eliminates the macroscopic defects in the WZ, significantly refines the grain size and reduces the composition difference between the stirring zone (SZ) and the base metal. The tensile fracture of TIG overlaying sample is located in the center of WZ, which has the lowest hardness and strength. FSP significantly improves the hardness and strength of the welding layer, with the fracture located in the thermo-mechanically affected zone (TMAZ) on the FSP advancing side. With the increase of rotation speed, the average grain size of SZ decreases, the strength of TMAZ and SZ increases, while the plasticity decreases.