6061-T6铝合金双轴肩搅拌摩擦焊接头组织与力学性能

Microstructure and mechanical properties of bobbin tool friction stir welding of 6061-T6 aluminium alloy

针对6 mm厚6061-T6铝合金板材,在主轴转速800 r/min,焊接速度150 mm/min参数下实现双轴肩搅拌摩擦焊接,并对一部分试件进行焊后热处理。对焊态试件和焊后热处理试件同时进行金相试验、拉伸试验和显微硬度试验对比分析。在焊态下,接头平均抗拉强度为203 MPa,达到母材的64%,接头在焊缝区32 mm的宽度区域内显微硬度出现不同程度的下降,显微硬度分布呈"W"型;接头经焊后热处理后,焊态下溶解消失的强化相重新析出,使接头组织重新得到强化,热处理态接头平均抗拉强度为292 MPa,达到母材的92%,整个焊缝区显微硬度均得到提高,焊态下"W"型显微硬度分布规律消除。

6061- T 6 aluminum alloy plates of 6 mm thickness were welded with bobbin tool friction stir welding technique under the rotating speed of 800 r/min and the welding speed of 150 mm/min. Part of the specimens were heat treated after welding.Metallurgical test, tensile test and microhardness test were done both on welded specimens and specimens after post weld heat treating. The average tensile strength of the welded joint was 203 MPa, which was 64% of that of the base material. The microhardness of the joint with the area of 32 mm width declined inordinately. The microhardness distribution was 'W' type. After post-weld heat treatment, strengthening phases in the area of the weld reprecipitated, which strengthened the microstructure. The average tensile strength of the joint with post-weld heat treatment was 292 MPa, which reached 92% of that of the base material. The microhardness of entire joint were improved. The 'W'-type microhardness distribution of the weld disappeared.