深冷处理对5A06铝合金FSW接头组织和力学性能的影响

为了避免铝合金焊接接头软化，提升接头力学性能，采用FSW对5A06铝合金进行对接试验，在转速为1 200 r/min、焊速为150 mm/min的条件下，将焊接接头加工成一定尺寸的金相试样和拉伸试样，研究深冷处理时间对5A06铝合金搅拌摩擦焊接头组织和力学性能的影响规律，采用显微组织观察试验、显微硬度试验和拉伸试验等方法，对接头组织和力学性能进行表征与分析。结果表明：深冷处理具有细化晶粒、促进析出相析出的作用，提高了接头力学性能；经过12 h深冷处理后，接头的抗拉强度和伸长率分别达到385.3 MPa和17.2%，与未经深冷处理的接头相比，分别提高了7.4%和23.7%。因此，深冷处理可以有效提升铝合金焊接接头的力学性能，为其更广泛的应用提供了理论基础和技术参考。

Effect of deep cryogenic treatment on microstructure and mechanical properties of friction-stir-welded joints of 5A06 aluminum alloy

In order to avoid softening and improve the mechanical properties of the aluminum alloy welded joints,the butt test of 5A06 aluminum alloy was carried out with FSW,and the welded joints were processed into metallographic samples and tensile samples of a certain size under the conditions of a rotating speed of 1 200 r/min and a welding speed of 150 mm/min,the effect of deep cryogenic treatment (DCT) time on microstructure and mechanical properties of friction-stir-welded joints of 5A06 aluminum alloy was investigated.The experiments were carried out by microstructure observation test,micro-hardness test and tensile test to characterize and analyze the joint organization and mechanical properties.The experiment results show that DCT can refine the grain and promote the precipitation of the second phase,thus the mechanical properties of the joints are improved.The tensile strength and elongation of the joints can reach 385.3 MPa and 17.2% respectively,which are increased by 7.4% and 23.7%,respectively after 12 h DCT compared with the joints without DCT.Therefore,DCT can effectively improve the mechanical properties of aluminum alloy joints and provide theoretical and technical basis for its application.