充型速度对半固态A1Si9Mg组织及性能的影响

采用倾斜冷却剪切流变法制备半固态A1Si9Mg合金熔体,流变压铸标准力学性能试样并进行了力学性能测定,用定量金相技术对力学性能试样的初生固相微观组织特征参数(固相率、晶粒尺寸和形状因子)进行了分析,研究了充型速度对半固态AlSi9Mg合金组织及性能的影响.研究结果表明:随着充型速度的提高,AlSi9Mg合金组织的初生固...

Influence of filling velocity on semi-solid microstructures and properties of AlSi9Mg alloy

Semi-solid AlSi9Mg alloy melt and corresponding standard test specimens were prepared by rheo-diecasting process on incline cooling and shearing bench.Then the specimens were tested on their mechanical properties.The characteristic parameters of primary solid phase（including solid fraction,diameter of grains and shape factor） were analyzed through quantitative metallographic techniques.The influence of fulling velocity on the semi-solid microstructures and properties of AlSi9Mg were researched into.The results show that： the primary solid fraction and shape factor of AlSi9Mg alloy first increase and then decrease,and the average diameter of grains becomes smaller at first and then becomes bigger along with the increase of the filling velocity.Simultaneously their mechanical properties change significantly,the Brinell hardness increases along with the filling velocity,but the tensile strength and impact toughness increase respectively to 275 MPa and 129.8 kJ/m2,and then begin to decline.In this experiment,a reasonable rate of filling is about 1.9 m/s.