Study on microstructure and wear properties of TiAl alloy deposited by laser melting
One-layer,three-layer and five-layer Ti-48Al-2Cr-2Nb alloy samples were prepared on TC4 substrate by coaxial laser powder-feeding deposition manufacturing process.The microstructure,crack morphology,wear surface morphology and phase composition of the deposited layer were analyzed by optical microscope(OM),scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and X-ray diffraction(XRD).The test results show that the number of cracks on the surface of the sample deposited with one layer is less,and the samples deposited with three and five layers have more surface cracks and the number of cracks is not much different.As the number of sedimentary layers in-creases,the microstructure in the sedimentary layer transits from a basket structure to a lamellar struc-ture,and the phase change in the structure is from a single phase α2 to α2+γ dual phase transition.As theα2 phase content decreases,the wear resistance decreases,and the average friction coefficient increases from 0.34 to 0.55.
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