关键词: 选择性激光熔化, 近&alpha, 钛合金, 裂纹, 开裂机理

Abstract:

The cracking  mechanism and inhibiting process  were   discussed through studying the crack morphology, propagation direction and crack source of a new near  α  phase titanium alloy specimen fabricated by SLM using scanning electron microscopy and so on.The experimental results show that:uneven notches arose from the sidewall of the specimen during fabricationas well as Ti3O,TiO,TiC which are hard and brittle.Under  the actions of residual stress,the cracks originate in the sidewall notches and expand  in the deposition along these hard and brittle compounds.When  the laser power is 140W,scanning speed is 450mm/s, layer thickness is 0.03mm,scanning space is 0.07mm,preheating temperature is 350℃ during  SLM  and preserve 1h,slow  cooling to room temperature,the number of cracks reduce significantly.

Key words: selective laser melting(SLM);near  , α , titanium alloy;cracking;cracking , mechanism