冷却介质对AZ31镁合金搅拌摩擦加工组织性能影响  

Effect of Cooling Medium on Microstructure and Property of AZ31 Magnesium Alloy in Friction Stir Processing

作　　者：王快社[1] 郭强[1] 王文[1] 郭韡[2] 吴楠[1] 

机构地区：[1]西安建筑科技大学冶金工程学院,西安710055 [2]中国重型机械研究院有限公司,西安710032

出　　处：《航空材料学报》2013年第1期33-37,共5页Journal of Aeronautical Materials

基　　金：国家自然科学基金(51074119);教育部高等学校博士学科点专项科研基金(20096120110012);西安市工业应用技术研究(CXY112414)

摘　　要：分别在空气、循环水和干冰酒精混合溶液中对AZ31镁合金板进行搅拌摩擦加工,研究了冷却介质对AZ31镁合金搅拌摩擦加工组织和性能的影响。结果表明:搅拌摩擦加工过程中峰值温度和150℃以上持续时间按照空气、循环水、干冰酒精混合溶液顺序依次递减。冷却介质对晶粒长大抑制效果明显,空气、循环水、干冰酒精混合溶液中搅拌区晶粒大小分别为3.9,3.0,1.8μm,和峰值温度变化趋势一致。由于晶界滑移的主导作用,干冰酒精混合溶液中搅拌区的硬度和强度低于循环水中,延伸率最高。空气和循环水冷却介质中,拉伸断口均表现为准解理断裂,但循环水中解理断裂所占比例明显高于空气中,在干冰酒精混合溶液中拉伸断口表现为微孔聚合型断裂。Friction stir process was applied to AZ31 magnesium alloy in the air, circulating water and mixture of dry ice and methanol respectively. The effect of cooling medium on microstructure and property of AZ31 magnesium alloy in friction stir process was studied in this paper. The results show that the peak temperature and duration of above 150℃ during friction stir processing are descending orderly in accordance with the order of the air, circulating water and mixture of dry ice and methanol. The impact which cooling medium inhibits growth of grain is obvious. The grain sizes of stir zone in the air, circulating water and mixture of dry ice and methanol are 3.9, 3.0 and 1.8 μm respectively. Furthermore, the grain size and peak temperature have the same changing trend. Due to the dominant function of gain boundary sliding, the hardness and strength of the stir zone in the mixture of dry ice and methanol are lower than that they are in the circulating water, and the elongation is highest. In the cooling mediums of the air and the circulating water, both tensile fractures exhibit quasi-cleavage crack, but the possessive proportion of cleavage crack in the circulating water is significantly higher than it in the air, the tensile fracture in the mixture of dry ice and methanol exhibits a typical ductile dimple-fracture.

关 键 词：冷却介质 AZ31镁合金 搅拌摩擦加工 组织 性能 

分 类 号：TG453.9[金属学及工艺—焊接] TG146.22[一般工业技术—材料科学与工程]