ABSTRACT

Friction stir welding (FSW) of ME20M magnesium alloy without and with preheating in different temperatures is carried out. The thermal histories of different preheating temperatures are investigated; the microstructure and mechanical properties of the weld joints are studied. The results show that by increasing the preheating temperature, the peak temperature, the grain size as well as the precipitate size are increased, and the precipitation is reduced. After FSW, the preferred orientation of the $⟨$0001$⟩$ crystal direction changes not to parallel but to normal direction, and the texture intensity improves. The microhardness and the tensile strength of the joints first increase and then decrease with the increase of the preheating temperature.

摘要

ME20M镁合金的摩擦搅拌焊接（FSW）在不同温度下不进行预热和进行预热。研究了不同预热温度的热历史；研究了焊接接头的组织和力学性能。结果表明，通过提高预热温度，峰值温度，晶粒尺寸和沉淀物尺寸增加，并且沉淀物减少。FSW之后，$⟨$0001$⟩$晶体方向改变为不平行，而是改变为法线方向，并且纹理强度提高。接头的显微硬度和抗拉强度随着预热温度的升高先增加然后降低。