Linear contraction of sand casting Mg-9Gd-3Y-0.5Zr alloy
(1. National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2. Shanxi Jianghuai Heavy Industry Co., Ltd., Jincheng 048000, China)
2. Shanxi Jianghuai Heavy Industry Co., Ltd., Jincheng 048000, China)
Abstract: The effect of geometric characteristics of castings on the linear contraction of sand casting Mg-9Gd-3Y- 0.5Zr alloy (VW93) was studied. The dimensions of free and restrained structure castings were precisely extracted by a 3D scanner and then used for the calculation of the contraction coefficient. The ratio of sand core volume to enveloping volume of casting (γ), was introduced to quantify the degree of constraint caused by sand cores. According to the statistical distribution of free contraction coefficients and the evolution of restrained contraction coefficients against γ, it is indicated that the free contraction coefficient of VW93 alloy equals 1.96%, and the restrained contraction coefficient declines linearly with the increasing γ, which supplies support on predicting the contraction of VW93 alloy through the geometric characteristic of castings.
Key words: free contraction; restrained contraction; sand casting; Mg-9Gd-3Y-0.5Zr alloy