Effect of Ca on Microstructure and Mechanical Properties of ZA85 Alloy

The effect of calcium on microstructure,mechanical properties of ZA85 alloy was studied.When the addition of Ca is 0.3％-0.9%,new phases do not form.Mechanical properties can be improved with increasing of the content of calcium,when the addition is 0.6%,the microhardness and ultimate strength increase to 117.5 HV and 164 MPa.The ultimate strength of casting alloy with an addition of 0.6% Ca is 149.5 MPa at 150 ℃ and the ultimate strength increase to 159.2 MPa after homogenizing treatment at 300 ℃ for 24 h.The morphology of room temperature fracture is brittle fracture and mainly consiste of planes.The planes decrease and ductile sockets increase at high temperatures,the fracture is ductile rupture.