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采用2000kN压力机,对半固态7A04合金进行了触变模锻实验。结果表明:半固态触变模锻成形可以获得组织致密、轮廓清晰、充型完整的成形件;半固态触变模锻件的微观组织和力学性能与坯料的制备方法有关,采用SIMA法所获得的成形件的微观组织为晶粒细小、均匀的再结晶组织,因此其组织致密,在拉伸过程中部分晶粒发生塑性变形,断口中多处出现撕裂棱,其力学性能明显好于挤压态坯料;在加热温度为600℃、保温时间为10min时SIMA坯料模锻件的伸长率和抗拉强度最高,接近于热挤压态棒料的力学性能,优于同等条件下挤压态合金的半固态模锻成形件,其抗拉强度和伸长率分别提高11.8%和78.5%。
Using 2000kN press, the semi-solid 7A04 alloy was subjected to thixoforming experiments. The results show that the microstructure and mechanical properties of semi-solid thixoforming die forgings are related to the preparation method of the billet. The results obtained by SIMA The microstructure of the shaped part is a fine and homogeneous recrystallized microstructure, so its structure is compact. Some of the crystal grains undergo plastic deformation during the stretching process, and many tear edges appear in the fracture. The mechanical properties are obviously better than those of the extruded State blank. When the heating temperature is 600 ℃ and the holding time is 10min, the elongation and tensile strength of SIMA blank die forging are the highest, close to the mechanical properties of the hot extruded bar, which is better than that of extruded alloy under the same conditions Semi-solid die forging, the tensile strength and elongation increased by 11.8% and 78.5% respectively.