Study On Microstructure Characteristics And Analysis Software Of Semi-solid Magnesium Alloy

The processing technology of semi-solid metals has very vast development foreground. Up to date, there are seldom study on semi-solid rheocasting process and the microstructure and properties of semi-solid magnesium alloy, and has no systematic investigation on the microstructural characteristics of semi-solid slurry. In this paper, the relationship between processing parameters of slurry preparation equipment and the slurry quality has been explored by studying the microstructure of semi-solid slurry before die-casting. The appreciation of slurry quality is generally completed by observing its microstructural characteristics. The results show one named rose microstructure has been produced with copper mould casting of semi-solid slurry, and it is different from a near-spherical structure made by semi-solid rheo-diecasting, nor a small dendritic structure got by liquid die-casting. The paper also gives four items to the appreciation of slurry quality though the microstructure characteristics of slurry, which are solid-phase factor, mean grain size, grain size distribution and grain shape distribution. Considering the problem that the existing software can not gives the quantitative measurement to the four items of semi-solid microstructure, a quantitative metallurgic image analyzing software of semi-solid alloy with C++ language in the platform of Visual Studio has been developed by utilizing technologies of quantitative metallography and digital image processing. The paper has provided theoretical basis and computation method of the four measuring items of microstructure for digital image processing by studying quantitative metallography. But grains and grain boundary must be identified automatically by computer in order to achieve computer automatic measurement. Used queue,the common data structure, the existing algorithm named "non-recurrence research method"has been improved. The traditional algorithm of edge detection has some defects such as complex calculation, long-playing computer treatment, difficult programming. A new algorithm named "magnetic lasso method", which adapted to the microstructure characteristics of semi-solid, has been developed. So that the computer processing difficulty has been depressed. The semi-solid microstructure analyzing software has a friendly interaction interface and it is easy and convenient to operate. The software was applied in analysis of microstructure of semi-solid magnesium alloy, and results show that the accuracy, reliability and reappearance could be satisfied of the common requirement of quantitative analysis.