Three-dimensional Reconstruction And Space Structure Characterization Of Rheocasting Aluminum Alloy

In this paper, use LSPSF semi-solid slurry preparation process and its device, and set up three different pipeline speed (60rpm,90rpm,120rpm) to prepare A356alloy semi-solid slurry by three different process conditions, and sample water quenched at605℃for the original sample. The microstructure of the samples were observed, and the two-dimensional quantitative metallographic analysis, primary phase a-Al and eutectic phase three-dimensional reconstruction and quantitative research.By observing the rheocasting A356alloy two-dimensional microstructure and quantitative analysis of two-dimensional microstructure, we can see:When the speed of rotating barrel is60rpm, most of the primary phase for the past nearly spherulite, there have been more rose-like grain and uneven distribution, the solid fraction is54%, the shape factor is0.64, and the average equivalent circular diameter is80.7μm. When the speed of rotating barrel is90rpm, the primary phase is nearly spherulite, high grain round and evenly distributed, the solid fraction is58%, the shape factor is0.86, and the average equivalent circular diameter is72.3μm. When the speed of rotating barrel is120rpm, most of the primary phase for the past nearly spherulite, the solid fraction is57%, the shape factor is0.79, and the average equivalent circular diameter is77.1μm. The results show that when the speed of rotating barrel is90rpm is the best process parameters.A356aluminum alloy rheocasting organization of primary phase and eutectic phase of the three-dimensional reconstruction, get primary phase and eutectic phase of the three-dimensional morphology and spatial distribution characteristics. You can clearly see from the three-dimensional morphology of the occlusal relationship between the grain and spatial location, this information is not acquired in the two-dimensional constitution diagram. Through quantitative research shows that: When the speed of rotating barrel is60rpm, the solid fraction is69.3%, the shape factor is0.58, and the average equivalent diameter is103.7μm. When the speed of rotating barrel is90rpm, the solid fraction is70.5%, the shape factor is0.81, and the average equivalent diameter is92.4μm. When the speed of rotating barrel is120rpm, the solid fraction is71.2%, the shape factor is0.72, and the average equivalent diameter is95.7μm. So90rpm for the best process parameters, this is consistent findings with the two-dimensional, but solid fraction increased, shape factor decreased, Equivalent diameter increased than the two-dimensional analysis of the structure, shape factor decreased. This is mainly due to three-dimensional measurement is accurate the actual information, which shows a three-dimensional quantitative analysis closer to the real grain.Reconstruction of the three typical grain in the semi-solid slurry:Rose-like grain, nearly spherulite and ellipsoidal grains. Get their three-dimensional structure and quantitative characterization of, volume are1740040μm3,514871μm3,931694μm3, surface are95205μm2,33080μm2,48409μm2, the shape factor are0.40,0.86,0.83, equivalent diameter are149.3μm,99.5μm,121.2μm. The difference of three grain shape factor just confirms the accuracy and reliability of the calculation of the shape factor.Rheological properties of semi-solid slurry were analyzed by A356three-dimensional morphology, the primary phase morphology and distribution has greatly improved the liquidity position of the liquid phase, so that the metal in the higher solid fraction having good flow properties.