以钨极氩弧(TIG)为加热热源,对压铸AZ91D镁合金进行表面局部重熔试验,研究了重熔区气孔内气体的本质及来源。结果表明:压铸镁合金母材特性是造成重熔区多气孔的主要原因,气孔内气体元素主要为N和H,其中N元素来自于空气中的N_2,H元素来自于镁合金压铸过程中熔剂中的水分、金属表面吸附的潮气以及金属腐蚀带入的水分。另外,电流较大时,重熔区域气孔问题更严重。 The surface of the die-casting AZ91D magnesium alloy was remelted by using TIG as heating source, and the nature and origin of the gas in the remelting stoma were studied. The results show that the matrix characteristics of die-cast magnesium alloy is the main reason for the multi-porosity in the remelting zone. The main gas elements in the pores are N and H, among which N is from N_2 in the air and H is from flux Moisture, the moisture adsorbed on the metal surface, and the moisture that the metal corrodes. In addition, the larger the current, remelting stomata problem is more serious.