Laser-assisted gas nitriding of selective Ti-6Al-4 V surfaces has been achieved during laser powder bed fusion fabrication by exchanging the argon build gas environment with nitrogen. Systematic variation of processing parameters allowed microdendritic TiN surface coatings to be formed having thicknesses ranging from a few tens of microns to several hundred microns, with TiN dendrite microstructure volume fractions ranging from 0.6 to 0.75; and corresponding Vickers microindentation hardness values ranging from ∼ 7.5 GPa–9.5 GPa. Embedded TiN hard layers ranging from 50 μm to 150 μm thick were also fabricated in the laser-beam additively manufactured Ti-6Al-4 V alloy producing prototype, hybrid, planar composites having alternating, ductile Ti-6Al-4 V layers with a hardness of ∼ 4.5 GPa and a stiff, TiN layer with a hardness of ∼8.5 GPa. The results demonstrate prospects for fabricating novel, additively manufactured components having selective, hard, wear and corrosion resistant coatings along with periodic, planar or complex metal matrix composite regimes exhibiting superior toughness and related mechanical properties.

在激光粉末床熔融制造过程中，通过用氮气交换氩气环境，实现了选择性Ti-6Al-4 V表面的激光辅助气体氮化。加工参数的系统变化使得可以形成厚度为几十微米至几百微米的微树枝状TiN表面涂层，而TiN树枝状微结构的体积分数为0.6至0.75。相应的维氏显微压痕硬度值约为7.5 GPa–9.5 GPa。还使用激光束增材制造的Ti-6Al-4 V合金制造了厚度范围为50μm至150μm的嵌入式TiN硬层，生产出具有交替，可延展的Ti-6Al-4 V层且硬度高的原型，混合，平面复合材料厚度约为4.5 GPa，且坚硬的TiN层的硬度约为8.5 GPa。