Research On Aluminum Alloy And High Chromium Cast Iron Prepared By Solid-Liquid Mixed Casting Process

Solid-liquid Mixed (SLiM) casting is a novel material preparation technology. In this process, a certain amount of alloy powder is added into melt and then immediately stirred until the powder is uniformly distributed among the melt. The powder has the same composition as that of the melt or has good wettability with the melt. This mushy made during the stirring process is then used for casting or other hot-processes. The experimental equipments of SLiM casting are designed and produced. The basic process parameters of SLiM casting for the aluminum alloys and high chromium cast iron preparation have been confirmed. The microstructure , properties , extrusion ability, and the subsequent reheating treatment of Al-Mn,Al-Cr,Al-Cu alloys and high chromium cast iron prepared by SLiM casting were studied via tensile strength test, DSC,OM and SEM analysis. The grain-refined mechanism of this technics was also analyzed. The results have been concluded as following:(1) The microstructures of as-prepared alloys are improved effectively by SLiM casting.The size of primary phase in Al-20Mn alloy prepared by SLiM casting can be controlled in 10μm and they present mainly spherical or equiaxed shape.Theα-Al of Al-20Cu alloy prepared by SLiM casting presents rosette or net-globoid, and the average size was approximately 70μm (added 200μm～96μm powders) or 50μm (added 74μm～43μm powders), which was obviously smaller than that of the Al-20Cu alloy made by semi-solid casting (120μm). The shape ofθI (CuAl2) in Al-40Cu alloys prepared by SLiM casting process was rounder than that of by others processes. The average size in length was decreased from 500μm (conventional casting) to 100μm (added 200μm～96μm powders) or 80μm (added 74μm～43μm powders); the average size in width was decreased from 80μm (conventional casting) to 40μm (added 200μm～96μm powders) or 30μm (added 74μm～43μm powders); the length-width ratio was reduced from 6 to 2.5. The microstructures of the Al-65Cu alloys prepared by the SLiM casting were composed ofθandη2 which shapes presented rosette or globoid with the average size below 35μm, which was obviously smaller than that of the semi-solid casting (100μm).The eutectic carbides in C15 high chromium cast iron produced by SLiM casting are more finer than that of by conventional casting, the carbides are transformed into spherical shape obviously and their length of is below 50μm. The dendritic austenites...