Additive manufacturing hybrid Ni/Ti-6Al-4V structural component via selective laser melting and cold spraying

The hybrid Ni/Ti-6Al-4V structural component was fabricated by an innovative hybrid additive manufacturing (AM) process, which combines two very effective AM techniques of selective laser melting (SLM) and cold spraying (CS), and an Eulerian model was used to study the deposition behavior of Ni on Ti-6Al-4V. The influence of vacuum heat-treatment on the interfacial microstructure and adhesion strength of the hybrid structural component was examined. After vacuum heat-treatment, the annealing twins were observed accompanying the healing-up of un-bonded interfaces between the deposited Ni particles, and the platelet α phase with the intergranular β phase was in-situ decomposed to acicular α′ martensite. The abnormal coarser α and fleck β, as well the multi-layer intermetallic near the interface between Ni/Ti-6Al-4V, were investigated. In addition, a reduction in bonding strength between deposit/substrate was evaluated after vacuum heat-treatment due to the formation of brittle intermetallic compounds.