中温回火对钛基体上镍基喷焊涂层组织和性能的影响

Influence of medium-tempering treatment on microstructure and properties of Ni based spray-welded coating on titanium substrate

关键词:  中温回火  喷焊涂层  钛基体  组织  性能

Key words:  medium-tempering  spray welded coating  titanium substrate  microstructure  properties

摘要:

对Ti-6A l-4V基体上火焰喷焊镍基涂层进行了中温回火处理,研究了涂层回火前后的显微组织和耐磨性能。结果表明,经中温回火处理后,喷焊层中析出了大量的硬质相,对喷焊层起到了弥散强化的作用,涂层组织的均匀性有较大提高,过渡层明显变厚,在整个横切面上的显微硬度变化更加平缓,软基体向硬涂层的性能变化梯度明显下降,喷焊表层的硬度比回火前略有提高,但其磨损失重仅为回火前的1/2.33。

Abstract:

The microstructure and properties of Ni based coating on Ti-6Al-4V alloys substrate fabricated by flames spray-welding and subsequently treated by medium-tempering were studied.The results show that a lot of hard particles are separated out after the medium-tempering treatment,which has the dispersion strengthen effect on spray-welded coating.After the medium-tempering treatment,the uniformity of coating's microstructure is improved,and the transition layer widens obviously;and the micro-hardness of coating changes more smoothly along depth direction,and the grads gradient of properties from soft substrate to hard coating decreases obvisously;and the micro-hardness of the spray-welded surface increases a little,but the wear loss of sample after tempering treatment is only equal to that of 1/2.33 of the before.