文章信息/Info

Title:

Friction Stir Processing on Fusion Welding Area of 7075 Aluminum Alloy

文章編號(hào):

1674-3962(2023)02-0174-07

作者:

李若琳; 朱彬; 程亮

（江蘇理工學(xué)院材料工程學(xué)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(guān)鍵詞:

7075; 鋁合金; TIG焊; 攪拌摩擦加工; 力學(xué)性能

Keywords:

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

分類號(hào):

TG453.9

DOI:

10.7502/j.issn.1674-3962.202209002

文獻(xiàn)標(biāo)志碼:

A

摘要:

7系超硬鋁合金廣泛應(yīng)用于航空航天以及汽車等領(lǐng)域，鎢極惰性氣體保護(hù)（tungsten inert-gas，TIG）電弧焊可用于構(gòu)件的修復(fù)，但熔焊缺陷以及專用絲材的缺乏使得熔覆層的強(qiáng)度不足。采用ER5356鋁合金焊絲對(duì)7075-T6合金進(jìn)行熔覆修補(bǔ)，并對(duì)TIG熔覆層進(jìn)行攪拌摩擦加工（friction stir processing, FSP），以期改進(jìn)熔覆層力學(xué)性能。固定TIG焊工藝參數(shù)和攪拌頭行進(jìn)速度，研究了攪拌頭轉(zhuǎn)速對(duì)熔覆層組織、力學(xué)性能以及斷裂行為的影響，結(jié)果表明：TIG熔覆區(qū)由粗大的樹枝晶組成，F(xiàn)SP消除了熔覆區(qū)的宏觀缺陷，顯著細(xì)化晶粒并減小了攪拌區(qū)與母材的成分差異。TIG熔覆試樣拉伸斷口位于硬度和強(qiáng)度最低的熔覆區(qū)中心。FSP顯著提高了熔覆層的硬度和強(qiáng)度，拉伸斷口位于前進(jìn)側(cè)的熱機(jī)械影響區(qū)。隨轉(zhuǎn)速增大，攪拌區(qū)平均晶粒尺寸降低，熱機(jī)械影響區(qū)和攪拌區(qū)的強(qiáng)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.