Bionic Structured Laser Nitriding and Anti-cavitation Performance of TC4 Alloy
In view of the problems of traditional laser gas nitriding,such as difficult to deal with large areas and easy to crack,a bionic structured laser gas nitriding method is proposed to improve the wear and corrosion resistance of titanium alloy surface by combining laser nitriding with texture.The bionic structured surfaces of stripe,square,positive triangle and positive hexagon are designed and fabricated,and the microhardness,microstructure and phase composition of the bionic structured units are analyzed in detail.The wear resistance and cavitation resistance of integral and structured nitriding samples are compared and analyzed,and the failure mechanism is studied.The results show that the average hardness of the nitride layer is 850 HV0.3,and the surface and middle part of the nitride layer are composed of dendrites and nitrogenous solid solution.The phase composition of the nitride layer includes a-Ti,TiN and TiNx(0＜x＜1).The wear of the nitride layer is mainly abrasive wear,and the change of surface structure plays a role in alleviating the cavitation damage.The wear resistance of the overall nitrided and structured nitrided specimens is about 3 times higher than that of the matrix,and the friction coefficient and wear amount of the nitrided specimens with the regular hexagonal structure are the lowest.The improvement of the cavitation resistance of the structured nitrided specimens is the result of the joint action of the surface hardness increase and the hardness characteristics between soft and hard.The laser nitriding composite biomimetic weaving technology is used to effectively improve the vapor corrosion resistance and wear resistance of the titanium alloy surface,and the prepared nitriding layer was uniform and crack-free.
laser gas nitridingTC4 alloybionic couplingabrasion resistanceanti-cavitation performance
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