CAJ | 학술논문

通过搅拌法制备A356?10%10SiC复合材料，并分别在0.1(重力条件)、25、50和75 MPa压力条件下进行该复合材料的直接挤压铸造成形，研究了铸态和 T6热处理后复合材料的微观组织及力学性能。结果表明：随着挤压力的增大，铸件的增强颗粒?孔洞团簇缺陷减少，并改善了增强颗粒与基体间的结合强度，拉伸强度、硬度和热膨胀系数增加。与铸态复合材料相比，T6热处理后复合材料的抗拉强度和硬度增大而热膨胀系数减小；在重力条件下凝固的复合材料断口处存在增强颗粒?孔洞团簇缺陷，而在挤压力下凝固的复合材料断口未观察到该缺陷，断口特征表明两者存在不同的断裂机制。
통과교반법제비A356?10%10SiC복합재료，병분별재0.1(중력조건)、25、50화75 MPa압력조건하진행해복합재료적직접제압주조성형，연구료주태화 T6열처리후복합재료적미관조직급역학성능。결과표명：수착제압력적증대，주건적증강과립?공동단족결함감소，병개선료증강과립여기체간적결합강도，랍신강도、경도화열팽창계수증가。여주태복합재료상비，T6열처리후복합재료적항랍강도화경도증대이열팽창계수감소；재중력조건하응고적복합재료단구처존재증강과립?공동단족결함，이재제압력하응고적복합재료단구미관찰도해결함，단구특정표명량자존재불동적단렬궤제。
A356-based metal matrix composites with 10%SiC particles of 10μm were fabricated by stir casting and direct squeeze casting process under applied pressures of 0.1 (gravity), 25, 50 and 75 MPa. The microstructures and mechanical properties of the as-cast and T6 heat-treated castings were investigated. The results show that as the applied pressures increase, the casting defects as particle-porosity clusters reduce and the incorporation between the particles and matrix can be improved. The tensile strength, hardness, and coefficients of thermal expansion (CTE) increase with the increase of the pressures. Compared with the as-cast composite castings, the tensile strength and hardness of the heat-treated casting are improved whereas CTEs tend to decrease in T6-treated condition. For the gravity cast composites, there are some particle-porosity clusters on the fracture surface, and the clusters are hardly detected on the fracture surface of the samples solidified at the external pressures. Different fracture behaviors are found between the composites solidified at the gravity and imposed pressures.