金属型重力铸造高强度铝铜合金

Metal Mold Gravity Casting High Strength Al-Cu Alloy

目的针对铝铜合金热裂敏感性高、难以进行金属型铸造的难题,研究其合金成分、铸造工艺、组织与性能的关系。方法首先充分分析铸造铝铜合金的凝固机制与特点,在ZL205A合金基础上,设计了新型合金成分以及两种铸造试样模,经过熔炼、铸造与热处理,获得砂型铸造与金属型铸造试样,进行力学性能测试、组织分析,并观察试样的抗热裂性。结果两种铸造试样都获得了较高的力学性能,铸态及T6态全部为等轴晶组织,成功避免了热裂问题,并提高了合金的力学性能;金属型铸造试制了油马达铸件。结论证明了通过铝铜合金的成分优化设计,以及含钪复合细化剂的合理匹配,采用金属型铸造获得等轴晶组织,进而避免粗大枝晶组织,是克服热裂问题的关键,从而实现金属型铸造高强度铝铜合金。

This work aims to research relationships of component, casting process, structure and performance of alloy to solve high hot fracture sensibility and metal mold casting difficulty of aluminum copper alloy. Firstly, solidification mechanism and characteristics of casting Al-Cu alloy were analyzed. On the basis of ZL205A alloy, new alloy compositions and two types of casting specimen molds were designed to have melting, casting and heat treatment to obtain specimen of sand casting and metal casting, to carry out mechanical property testing, structure analysis, and observe anti-fracture property. Both the two kinds of casting specimens achieved high mechanical properties, i.e., the all equi-axial structure appeared in both casting and after T6 treatment, which successfully avoided the problem of hot fracture and improved alloy mechanical properties. Oil motor casting was made experimentally by metal mold casting. This proves that by optimization design of A1-Cu alloy composition and proper allocation of Sc containing composite refiner, equi-axial structure can be acquired by metal casting, that can avoid coarse den- drite structure. It is the key of anti-hot-cracking. It also provides the accessibility of metal mold casting high strength Al-Cu alloy