Resolving the porosity-unmelted inclusion dilemma during in-situ alloying of Ti34Nb via laser powder bed fusion
By Sheng Huang, R. Narayan, Joel Heang Kuan Tan, Swee Leong Sing, W. Y. Yeong. 2021
136 citations recorded by the source corpus.
Abstract A parametric experimental study on the role played by the power (P), velocity (VL) and profile (top hat or Gaussian) of the laser on the porosity, inclusion content and microstructural evolution of in-situ alloyed laser powder bed fusion (LPBF) manufactured Ti34Nb was conducted. For this, alloys were printed with three sets of processing parameters, in which the above-mentioned parameters were varied but the energy density was held constant. A detailed tomographic and microstructural investigation of these alloys was followed by tensile tests. Observations of melt pools in the single tracks and single stripes were complemented by thermal finite element method (FEM) simulations that studied their evolution. Results show that a top hat laser profile combined with high P (> 650 W), high VL (> 650 mm/s) and short stripe width scanning strategy forms a large single stripe melt pool that moves slowly and has a low aspect ratio. The large and slow melt pool allows Nb to melt efficiently and minimizes its unmelted content while the low melt pool aspect ratio prevents keyholing that can otherwise result in porosity. These melt pool attributes also favor the formation of a columnar β-Ti microstructure with a strong {100} texture, which has the ideal combination of strength and elastic modulus. The mechanisms of microstructural evolution were explained and the scope of this parameter optimization principle was discussed in the context of further improving the properties of this alloy.
Subfields: Materials Chemistry, Mechanical Engineering
View Paper: https://www.semanticscholar.org/paper/81a0108e22ef4463b9c27748738e6bb462eb8911
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In Mechanical Engineering
Citations in the corpus
- Recent innovations in laser additive manufacturing of titanium alloys (2024, methodology): “…this challenge, several solutions have been proposed: (i) adopting ultrafine β - isomorphous powders [106], (ii) using a top-hat profile laser [107], (iii) using a high input laser energy density [104], (iv) using cross-hatching style with an angle of 74 ◦ between the layers [108], and (v)…”