A novel rapid alloy development method towards powder bed additive manufacturing, demonstrated for binary Al-Ti, -Zr and -Nb alloys

Freddy Leijon,Sebastian Wachter,Zongwen Fu,Carolin Körner,Svein Skjervold,Johan Moverare

doi:10.1016/j.matdes.2021.110129

Freddy Leijon, Sebastian Wachter + Show 4 more

Open Access

https://doi.org/10.1016/j.matdes.2021.110129

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Abstract

Powder bed fusion (PBF) methods offer the best material properties among metal additive manufacturing (AM) processes. Yet, alloy development for PBF is only at its infancy and has a great untapped potential. This originates from the high solidification rate within the melt pool and to exploit the full potential of materials produced by PBF methods, a diligent work lies ahead. This paper presents a high-throughput method to rapidly screen large compositional alloy intervals experimentally for their PBF feasibility, which can drastically reduce the time needed for alloy development and provide valuable data for modelling. Our method consists of two steps; co-sputtering and electron beam re-melting. First step produces an alloy gradient film on a sheet substrate. The film is then re-molted to produce a PBF mimicked microstructure. The method is successfully demonstrated on binary systems; Al -Ti, -Zr and -Nb and produced gradients in compositional ranges of 3–50 wt%Ti, 1–15 wt%Zr and 2–15 wt%Nb over a length of 200 mm. From the produced materials, the alloying efficiency could be investigated and determined regarding hardness and grain refinement. Zr shows the highest strength contribution per at% and the best grain refinement at low levels. However, at higher levels grain refinement efficiency decreases for Zr.

Highlights

Alloy development for additive manufacturing (AM) is currently in its infancy
Of traditional wrought and casting alloys for AM. This led to aluminium alloys such as AlSi7Mg0.6, AlSi10Mg, and the titanium alloy TiAl6V4, which all share the same composition as their traditional counterparts but with some enhanced properties due to the refined microstructure [1,2], resulting from the high solidification rate
A re-molten slice of an Al-Zr deposition can be seen in Fig. 6, and with the naked eye it is clear that the surface roughness increases as the alloy content increases, this is true for all electron beam (EB) parameters and alloy gradients

Summary

Introduction

Alloy development for additive manufacturing (AM) is currently in its infancy. Of traditional wrought and casting alloys for AM. This led to aluminium alloys such as AlSi7Mg0.6, AlSi10Mg, and the titanium alloy TiAl6V4, which all share the same composition as their traditional counterparts but with some enhanced properties due to the refined microstructure [1,2], resulting from the high solidification rate. The alloy development has shifted towards new alloy concepts developed to take advantage of the high solidification rate.

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