A new idea of homogeneity isomerism is proposed in this work to break through the single restriction that traditional homogeneous powder metallurgy materials take refining particles as the only modification method. AA2024 alloy powders of different diameters are mixed in a certain proportion through low-energy ball milling, and then a kind of mixed crystal material is successfully fabricated by hot pressing sintering. The results show that the grain morphology of the traditional sample sintered with single-diameter particles tends to become irregular polygon shape, while the grain morphology of the mixed crystal materials forms a special structure in which larger grains are coated with smaller grains. Compared with the former, when the proportion of coarse particles is 20% (mass fraction), the tensile strength increases by 38.8%; when the proportion of coarse particles is 50%, the elongation increases by 14%. The mixed crystal material exhibits a mixed fracture mechanism of intergranular fracture and transgranular fracture, and the pinning effect of the second phase on the dislocation is more obvious, so the properties of the alloy are improved significantly. The above research provides a new idea for the preparation of high-performance homogeneous isomeric mixed crystal materials.

为了突破传统均质粉末冶金材料以细化颗粒为唯一改性方式的单一限制，本工作提出了均质异构的新思想。将不同直径的AA2024合金粉末通过低能球磨按一定比例混合，然后通过热压烧结成功制备出一种混晶材料。结果表明，单一直径颗粒烧结的传统样品晶粒形貌趋向于变成不规则的多边形，而混晶材料的晶粒形貌则形成较大晶粒包覆较小晶粒的特殊结构。与前者相比，当粗颗粒比例为20%（质量分数）时，抗拉强度提高了38.8%；当粗颗粒比例为50%时，伸长率提高14%。混晶材料表现出沿晶断裂和穿晶断裂的混合断裂机制，第二相对位错的钉扎作用更加明显，从而显着提高了合金的性能。上述研究为制备高性能均相异构混晶材料提供了新的思路。