Study On Heat Treatment Process Of Laser Deposition TC4/TC11 Gradient Composite

In recent years,gradient composites have been increasingly used in life and industry.Since there are few studies on TC4/TC11 titanium aloy,this paper focuses on the effect of heat treatment on the microstructure and properties of TC4/TC11 titanium aloy.This paper,based on the comparative study on the microstructures,mechanical properties,tensile fractures,microhardnesses,friction and wear properties of laser deposited TC4/TC11 direct transition pieces,TC4/TC11 component gradient parts and TC4 titanium aloy samples under different heat treatments,the ways to improve the microstructures and properties of samples were explored.The results show that through the analysis of microstructures and properties of the TC4/TC11 direct transition samples under different heat treatments,it is found that when the heat treatment temperature reaches 970?,the microstructures on their two sides are featured by basket-weave structure and more even.In addition,the grain boundary ? phase disappears entirely.There is almost no existence of transitive interface.Through the analysis of microstructures and properties of the TC4 samples under different heat treatments,it is found that when the samples are dissolved at 970? for 2h and then treated by aging heat treatment,their structures turn to be constituted by equiaxed ? phase,basketweave ? and transformed ? phase,which results in the optimized textural parameters.Based on the analysis of microstructures and properties of the TC4/TC11 titanium aloy specimens with different composition gradient under different heat treatments,it is found that when the temperature of solution and aging treatment raises to 970?,length-width ratio of ? laths is less than that of other heat treatment samples.Both the globular ? phases and the short bar ? phases are significantly increased.Compared with the 0 layer transition zone and the 1 layer transition zone,the microstructures of the three-layer transition zone are more uniform and orderly,and the transition interface almost disappears.With the increase of the number of transition layers,the strength and plasticity of solid aging solution samples with different component gradients are increased.Through the analysis of microstructures and properties of the TC4/TC11 direct transition samples under different gradient heat treatments,It is found that compared with other samples,the strength of samples with heat treatment at 850? on the TC4 side and with heat treatment at 750? on the TC11 side is not reduced greatly.Moreover,its plasticity is remarkably enhanced.So it has excellent integrated mechanical properties.