Friction stir welding of AZ31 magnesium alloys processed by equal channel angular pressing
来源期刊：Rare Metals2008年第4期
论文作者：ZHANG Bing, YUAN Shouqian, and WANG Xunhong Department of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an , China
文章页码：393 - 399
摘 要：Equal channel angular pressing （ECAP） is an effective thermo-mechanical process to make ultrafine grains. An investigation was carried out on the friction stir welding （FSW） of ECAPed AZ31 magnesium alloys with a thickness of 15 mm. For different process parameters, the op-timum FSW conditions of ECAPed AZ31 magnesium alloys were examined. The basic characterization of weld formation and the mechani-cal properties of the joints were discussed. The results show that the effect of welding parameters on welding quality was evident and weld-ing quality was sensitive to welding speed. Sound joints could be obtained when the welding speed was 37.5 mm/min and the rotation speed of the stir tool was 750 r/min. The maximum tensile strength （270 MPa） of FSW was 91% that of the base materials. The value of micro-hardness varied between advancing side and retreating side because of the speed field near the pin of the stir tool, which weakened the de-formed stress field. The value of microhardness of the welding zone was lower than that of the base materials. The maximum value was lo-cated near the heat-affected zone （HAZ）. Remarkable ductile character was observed from the fracture morphologies of welded joints.
摘要：Equal channel angular pressing （ECAP） is an effective thermo-mechanical process to make ultrafine grains. An investigation was carried out on the friction stir welding （FSW） of ECAPed AZ31 magnesium alloys with a thickness of 15 mm. For different process parameters, the op-timum FSW conditions of ECAPed AZ31 magnesium alloys were examined. The basic characterization of weld formation and the mechani-cal properties of the joints were discussed. The results show that the effect of welding parameters on welding quality was evident and weld-ing quality was sensitive to welding speed. Sound joints could be obtained when the welding speed was 37.5 mm/min and the rotation speed of the stir tool was 750 r/min. The maximum tensile strength （270 MPa） of FSW was 91% that of the base materials. The value of micro-hardness varied between advancing side and retreating side because of the speed field near the pin of the stir tool, which weakened the de-formed stress field. The value of microhardness of the welding zone was lower than that of the base materials. The maximum value was lo-cated near the heat-affected zone （HAZ）. Remarkable ductile character was observed from the fracture morphologies of welded joints.
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