摘要
目的在保证搅拌速度一定时,针对8 mm厚的7A52铝合金,在不同焊接速度下采用搅拌摩擦焊(FSW)进行焊接试验,研究其焊接接头的显微组织及力学性能。方法利用搅拌摩擦焊机进行对接焊接,焊后制取金相试样观察焊接接头宏观形貌和显微组织,并测定其力学性能。结果7A52铝合金FSW焊接接头焊核区的面积随着焊接速度的增大而增大,当焊接速度为250mm/min时,焊接接头的焊核区面积最大,焊核区的显微组织都为细小的等轴晶,焊接接头横截面的焊核区呈明显"洋葱环"的形貌,而热力影响区的结构特征则呈现出了较高的塑性变形流线层。焊接接头显微硬度分布都呈现出"W"形变化,在焊接速度为150 mm/min时,焊接接头的平均抗拉强度能达到452 MPa,达到了母材抗拉强度的89%。结论通过对不同焊接速度下7A52铝合金FSW焊接接头的组织和性能进行研究,得到了不同焊接速度下焊接接头组织和力学性能。
ABSTRACT:When the stirring speed was constant, the welding test for 7A52 alloy aluminum with a thickness of 8 mm was conducted using friction stir welding ( FSW) at different welding speeds. The microstructure and mechanical properties of welded joints were studied. The friction stir welding machine was used for butt welding, the metallographic specimen was made after welding to observe macro and microstructure of the welding joint, and its mechanical properties were also meas-ured. The area of 7A52 aluminum FSW welding joints in the welded zone increased as the welding speed increased, when the welding speed was 250 mm/min, the welding joint area was the biggest. The microstructure of welded zone was fine e-quiaxed crystal, the welded zone on the cross section of the welding joint showed obvious morphology of onion rings, and the structural features of the heat affected zone showed relatively high plastic deformation streamline. The distribution of the hardness of welded joints showed a "W" shape change. When the welding speed was 150 mm/min, the average tensile strength of welded joints was 452 MPa, reaching 89% of the tensile strength of the base material. In conclusion, the effects of different welding speeds of 7A52 aluminum alloy on the microstructure and the property of the friction stir-welding joint were studied. The microstructure and properties of welded joints at different welding speeds were obtained.
出处
《精密成形工程》
2015年第5期72-76,共5页
Journal of Netshape Forming Engineering
关键词
7A52铝合金
搅拌摩擦焊
显微组织
力学性能
7A52 aluminum alloy
friction stir welding
microstructure
mechanical property
