Research On The Solid-Liquid Mixed Casting

High chromium aluminium alloys are useful light weight materials with excellent wear, heat and corrosion resistance. But it is hard to prepare by conventioned casting technology due to the formation of coarse intermetallic compound phase, which restrain the practical application of this kind of alloy. In this thesis, a novel technology termed as Solid-Liquid Mixed Casting was employed to prepare Al-10Cr alloys, the effects of processing parameters on the microstructures and mechanical properties were investigated.The main content of this thesis includes following four respects:1) The Solid-Liquid Mixed Casting(S-L-M-C) equipments,die-casting mould and extrusion mould were improved. 2) The Solid-Liquid Mixed Casting processing was researched, the processing parameters were optimized, the microstructure and mechanical properties of die-casting ingots were investigated. 3) semi-solid thixoextrusion and rheoextrusion processes of the Solid-Liquid Mixed Casting Al-10Cr alloy mushy were researched. 4) The wear and abrasion and also the erosion resistance of the Al-10Cr alloy was discussed.In the end, the conclusions are drawn as following:1) The improved S-L-M-C equipment is composed of the semi-solid insulating unit, the stirring system, the powder addition device, the discharge unit and other additional units. 2)The die-casting mould and extruding mould are integrated and are convenient to disassemble or assemble.3) The S-L-M-C Al-10Cr alloy with homogeneous microstructures were prepared by this equipment under the optimized processing parameters of the stirring rate 500rpm, the temperature of mushy 1073K and of the die-casting mould 873K. The powder is added into melt in batch.4) The smallest size of the intermetallic compound phases and the best room temperature mechanical properties of die-casting ingot was obtained when the mass ratio of the added powder to the melt was up to 0.4, σ_b=119.3MPa.5) Though rheoextrusion processing and thixoextrusion processing can refine the microstructures of the Al-10Cr alloy, it is less than that of the powder/melt ratio and powder particle size. The tensile strength of the thixoextrused samples are higher than that of the rheoextrused samples.6) powder/melt ratio and powder particle size have remarkable effects on the abrasion resistance of the Al-10Cr alloy. The...