Additive manufacturing of strong and ductile Ti–6Al–4V by selective laser melting via in situ martensite decomposition

By W. Xu, Milan Brandt, S. Sun, J. Elambasseril, Q. Liu, K. Latham, K. Xia, M. Qian. 2015

1,149 citations recorded by the source corpus.

Abstract Novel ultrafine lamellar (α + β) microstructures comprising ultrafine (∼200–300 nm) α-laths and retained β phases were created via promoting in situ decomposition of a near α′ martensitic structure in Ti–6Al–4V additively manufactured by selective laser melting (SLM). As a consequence, the total tensile elongation to failure reached 11.4% while maintaining high yield strength above 1100 MPa, superior to both conventional SLM-fabricated Ti–6Al–4V containing non-equilibrium acicular α′ martensite and conventional mill-annealed Ti–6Al–4V. The formation and decomposition of α′ martensite in additively manufactured Ti–6Al–4V was studied via specially designed experiments including single-track deposition, multi-layer deposition and post-SLM heat treatment. The essential SLM additive manufacturing conditions for Ti–6Al–4V including layer thickness, focal offset distance and energy density, under which a near α′ martensitic structure forms in each layer and then in situ transforms into ultrafine lamellar (α + β) structures, were determined. This is the first fundamental effort that has realized complete in situ martensite decomposition in SLM-fabricated Ti–6Al–4V for outstanding mechanical properties.

Subfields: Automotive Engineering, Materials Chemistry, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/634b574741ff8fa2fac1120710616ecbb25575fb

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In Automotive Engineering

1. T. Mukherjee
2. T. DebRoy
3. H. Wei
4. A. Fatemi
5. Amitava De
6. N. Sanaei
7. Wei Zhang
8. J. Elmer

In Materials Chemistry

1. T. Mukherjee
2. A. Fatemi
3. T. DebRoy
4. H. Wei
5. N. Sanaei
6. D. StJohn
7. N. Phan
8. M. Bermingham

In Mechanical Engineering

1. T. DebRoy
2. T. Mukherjee
3. H. Wei
4. Amitava De
5. A. Fatemi
6. J. Elmer
7. Wei Zhang
8. N. Sanaei

Citations in the corpus

• Laser cladding as repair technology for Ti–6Al–4V alloy: Influence of building strategy on microstructure and hardness (2015, background): “The martensite is also quite different from the duplex - structure and it is also less stable as it can undergo decomposition under the influence of temperature [22].”
• Fatigue of additive manufactured Ti-6Al-4V, Part I: The effects of powder feedstock, manufacturing, and post-process conditions on the resulting microstructure and defects (2020, background): “The α′ phase decomposes upon reheating at temperatures as low as 673 K [32].”
• Mechanism of stress relaxation and phase transformation in additively manufactured Ti-6Al-4V via in situ high temperature XRD and TEM analyses (2020, background): “reported that near-complete martensite decomposition can be achieved at a temperature as low as 400°C [44].”