Effect Of Casting Process On The Microstructure And Properties Of ZL114A Aluminium Alloy Castings

The differences in the microstructure and properties of a ZL114A casting were comparatively investigated using a low pressure casting process and a differential pressure casting process. The results showed that the as-cast microstructure of the alloy under the two casting processes mainly consisted of α-Al matrix, eutectic silicon phase, and the coarse eutectic phase in the as-cast state was transformed into fine spherical shape after T6 treatment. The average values of tensile strength, yield strength and elongation of the alloy under the differential pressure casting process are 345 MPa, 306 MPa and 5.3%, respectively, which are 6.2%, 9.3% and 17.8% higher than those of the low pressure casting process. This is due to the differential pressure casting process in the liquid metal solidification process can provide better shrinkage capacity, the alloy microstructure is more dense, the alloy grain refinement effect is good, and the second phase distribution in the microstructure is more diffuse and uniform, the second phase strengthening effect is good. The fracture mechanism of the alloy in both ways is a mixed tough-brittle type, but the plasticity characteristics of the alloy are more obvious under the differential pressure casting process.