Study Of Rheological Mold Filling Theory For Semi-solid Alloy Melt

Because the cost of semi-solid alloy thixoforming technology is high, and heating of ingot causes easily second inclusion, but the semi-solid alloy melt rheoforming technology has some advantages, such as short filling process, low cost and so on, so it has become more and more respected in colleague in the worldwide. Semi-solid alloy melt rheologic mold filling theory is one of the technologic theories of the semi-solid alloy melt rheoforming technology. Now the semi-solid alloy melt rheologic mold filling theory has not been researched systematically and completely, which will directly affect the popularization and application of the semi-solid alloy melt rheoforming technology. The rheologic filling ability of semi-solid alloy melt, the evolving rule of the original structure phase along filling process, the limit length of rheological mold filling of semi-solid alloy melt and the critical conditions of the mould cavity filled with the semi-solid melt were studied systematically in this paper.The influence of the characteristic parameters of the semi-solid alloy melt original structure on the mold filling ability was studied through experimental method; The influence of solid phase fraction, grain size and shape factor of original structure phase on the mold filling ability was analyzed; The mathematical representation between original structure character parameters and filling length was established through regression analysis. In addition, the influence of filling pressure and filling speed on the filling ability was studied, and the relationship between filling length and filling pressure and speed respectively was established.Using the spiral sample of semi-solid squeeze casting, the evolving rule of solid phase fraction, grain size and shape factor of the semi-solid alloy melt original phase was investigated by the method of quantitative metallic phase. The influence of filling pressure and speed on the original structure evolution along filling process was found. The rheological filling mode of the semi-solid alloy melt filling the spiral sample was analyzed. The results show that rheological mode was uniform, and the original structure of semi-solid alloy melt before filling, filling pressure and filling speed will not bring the conversion from uniform rheology to separate rheology in the condition of this experiment.Taking semi-solid alloy melts filling in circle pipe and rectangular pipe as example,...