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半固态连接被认为是一种连接合金的可能的方法。研究了AZ91镁合金半固态搅拌摩擦焊接的机理。将2块7.5 mm厚的AZ91镁合金试件和1块2 mm厚的Mg 25%Zn中间层放在加热板上,加热到所需温度并保温3min后,采用旋转搅拌头搅拌焊缝。将加热板在台车上以4.6 cm/min的恒定速度运动。同时,对一个样品进行无中间层焊接。使用扫描电子显微镜和光学显微镜研究焊接过程中搅拌速度、搅拌头形状和温度的影响。结果表明,中间层降低了焊接温度;升高温度、加快搅拌速度、采用圆形搅拌头代替槽形搅拌头都能增大搅拌区的宽度。在焊接过程中,可能存在某些机理,从而有助于获得良好的的冶金结合,例如氧化层消失、液相混合、液球连接、液体渗入基体、从大量液球基体金属进入焊缝区。
Semi-solid connection is considered as a possible way to connect the alloy. The mechanism of semi-solid friction stir welding of AZ91 magnesium alloy was studied. Two 7.5 mm thick AZ91 magnesium alloy specimens and a 2 mm thick Mg 25% Zn interlayer were placed on a hot plate, heated to the desired temperature and held for 3 minutes, and then the rotary stirrer was used to stir the weld. Move the hot plate on the trolley at a constant speed of 4.6 cm / min. In the meantime, there is no middle layer welding on a sample. Scanning electron microscopy and optical microscopy were used to study the effects of stirring speed, head shape and temperature during welding. The results show that the middle layer reduces the welding temperature; the temperature is increased, the stirring speed is accelerated, and the width of the stirring zone can be increased by adopting a circular stirring head instead of a groove-shaped stirring head. Certain mechanisms may exist during the welding process to help achieve good metallurgical bonding, such as the disappearance of oxide layers, liquid phase mixing, liquid crystal balling, liquid penetration into the substrate, and passage of a large amount of liquid metal base metal into the weld zone.