Taking Ti-44Al-8Nb-xC(x=0,0.3,0.6)alloys as the research object,the effects of three different carbon contents and two aging temperatures on the microstructure,microhardness and high-temperature tensile properties were studied.The results show that when the carbon content increases to 0.6％,Ti2AlC precipitates in the alloy.When the aging temperature increases from 800℃to 900 ℃,Ti3AlC precipitates in the alloy containing carbon.The increase in carbon content and aging temperature are all beneficial to improving the microhardness and tensile strength at 850 ℃ of the alloy,where the highest microhardness is(477.6±9.1)HV0.3,and the highest tensile strength at 850 ℃ is(605.07±5.01)MPa,which increases by 32.7％compored to the lowest tensile strength.The elongation is related to the number and size of carbides,and all the tensile fractures show brittle fracture.The alloy with 0.3％carbon has the best plasticity when aged at 900℃,the highest elongation is 5.41％±0.42％,which increases by 67.5％compared to the lowest elongation.
high Nb-TiAl alloycarbon contentheat treatmentmicrostructuremechanical properties
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