Research On Microstructure And Mechanical Properties Of K4169Alloy In Sand Casting

In this paper, K4169alloys were prepared by vacuum induction melting. The effectof different sand and wall thickness on the microstructure and mechanical properties hasbeen studied. The effect of heat treatment on the microstructure and mechanicalproperties has been further studied. The phase constitution of K4169alloy ischaracterized by X-ray diffraction. The microstructure and phase composition wereinvestigated by optical microscope and scanning electron microscopy affiliated withenergy dispersive X-ray spectroscope. The mechanical properties of different mouldtypesand different wall thickness were studied by the Instron universal testing machine.The analysis of X-ray diffraction indicates that K4169alloy was composed of the γphase matrix and the Laves phase before heat treatment. And the volume fraction ofLaves phase decreases and newly δ phase formatted after heat treatment. The analysis ofmicrostructures indicates that the secondary arm spacing of K4169alloy decreases withthe decreasing of the wall thickness before and after heat treatment. After heat treatmentthe volume fraction of Laves and the segregation degree both decrease.The analysis of the mechanical properties of K4169alloy indicate that the tensilestrength, yield strength, plasticity increases with the decreasing of the wall thicknessbefore and after heat treatment. Before heat treatment, the tensile strength increases15.3%at the thickness of6mm than18mm with zircon sand casting. The tensile strengthincreases14%with quartz sand casting. After heat treatment, the tensile strengthincreases65%, it gets1345.7MPa with zircon sand casting. The tensile strength of quartzsand casting alloy also increases63%. The tensile strength gets1301.9MPa.