研究了激光冲击AZ31镁合金在不同退火条件下的力学性能及其断口形貌。结果表明：随着退火温度及退火时间的增长，合金的硬度逐渐降低；在相同的退火时间(30 min)条件下，抗拉强度及延伸率在200 ℃~350 ℃温度区间内，随着温度的升高逐渐增加，在400 ℃退火后迅速降低；在相同的退火温度(350 ℃)条件下，随着时间的延长抗拉强度逐步降低，伸长率先略有增加然后降低；最佳的退火温度及时间为350 ℃和30 min，抗拉强度和断裂伸长率分别达到342 MPa 及18%。不同的退火工艺对激光冲击后合金的断口形貌有明显影响，在350 ℃和30 min 退火后断口呈现明显的韧性特征。

The variation of mechanical properties and fracture morphology of AZ31 Magnesium alloy after laser shock processing (LSP) at different annealing states is investigated．The results show that the hardness of AZ31 Magnesium alloy decreases when the annealing temperature and holding time increase. When the holding time is 30 min, the tensile strength and elongation go up with the annealing temperature rises from 200 ℃ to 350 ℃ while decline quickly when the annealing temperature reaches to 400 ℃ ; when the annealing temperature is 350 ℃ , with holding time goes on, tensile strength reduces gradually but the elongation first increases and then decreases. The best annealing state is 350 ℃ and 30 min when the tensile strength and the elongation at break are 342 MPa and 18% , respectively. Different annealing treatments have apparent effect on the fracture morphology of AZ31 Magnesium alloy after LSP, it presents remarkable toughness fracture surface morphology when the annealing state is 350 ℃ and 30 min.