超声冲击处理对7A52铝合金焊接接头表层组织及性能的影响

发布时间：2018-03-31 16:51

本文选题：超声冲击　切入点：A铝合金　出处：《表面技术》2015年06期

【摘要】：目的研究超声冲击处理对7A52铝合金焊接接头表层组织及性能的影响。方法用双丝MIG焊接方法对7A52铝合金进行焊接,采用UIT-125型超声冲击机对其焊接接头进行全覆盖处理;通过金相显微镜,对超声冲击处理后的焊接接头组织变化规律进行观察分析;利用显微硬度计和磨擦磨损试验机测试研究其接头力学性能。结果超声冲击处理后,焊趾处形成相对连续、均匀、光滑的过渡圆弧,可以有效地缓解焊接接头的应力集中,7A52铝合金焊接接头表面得到了明显强化,形成一层致密的塑性变形层,接头表面晶粒细化,母材的表层塑性变形厚度可达15μm左右,热影响区的表层塑性变形厚度可达25μm左右,显微硬度和耐磨性显著提高。结论经超声冲击处理后,7A52铝合金焊接接头表面的塑性变形层最厚处可达20μm左右,形成了具有大致平行于焊接接头表面择优取向的形变织构。沿厚度方向1.5 mm内,热影响区的硬度最高可达162HV,焊缝区的最高硬度为113HV,相比之前提高了21.5%,表层的耐磨性得到较为明显的提高。
[Abstract]:Objective to study the effect of ultrasonic shock treatment on the surface structure and properties of 7A52 aluminum alloy welded joint. Methods double wire MIG welding method was used to weld 7A52 aluminum alloy, and UIT-125 ultrasonic impact machine was used to cover the welded joint. The microstructure changes of welded joints after ultrasonic impact treatment were observed and analyzed by metallographic microscope. The mechanical properties of welded joints were tested by microhardness tester and friction wear tester. Results after ultrasonic impact treatment, the mechanical properties of welded joints were studied by means of microhardness tester and friction wear tester. A relatively continuous, uniform and smooth transition arc is formed at the toe, which can effectively relieve the stress concentration of the welded joint and obviously strengthen the surface of the welded joint, forming a dense plastic deformation layer, and the grain on the surface of the joint is fine. The surface plastic deformation thickness of the base metal can reach about 15 渭 m, and that of the heat affected zone can reach about 25 渭 m. The microhardness and wear resistance were improved significantly. Conclusion the plastic deformation layer on the surface of welded joint of 7A52 aluminum alloy can reach about 20 渭 m after ultrasonic impact treatment. A deformed texture with a preferred orientation approximately parallel to the surface of the welded joint is formed. Within 1.5 mm along the thickness direction, The hardness of HAZ is up to 162HVand the highest hardness of weld zone is 113HV. the wear resistance of the surface layer is obviously improved compared with that of before.
【作者单位】：内蒙古工业大学材料科学与工程学院;
【基金】：国家自然科学基金资助(51165026)~~
【分类号】：TG407;TG663

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