SLM Fe50Mn30Co10Cr10 metastable high entropy alloy with Al-Ti addition: Synergizing strength and ductility

Developing high entropy alloys that possess both high strength and high ductility have achieved significant progress in recent years. In this study, the metastable high entropy alloy Fe50Mn30Co10Cr10 with Al-Ti addition was formed by SLM technology. The effect of Al-Ti addition on the microstructure and mechanical properties were investigates. The results shown that: with the addition of Al-Ti addition content, the grain size of the alloy decreases gradually. And also the TiAl intermetallic compounds and nanoscale L12 phase are precipitated in the matrix. The phase transformation induced plasticity (TRIP) effect and twin-induced plasticity (TWIP) effect can be activated during the plastic deformation of the alloy. Strength and ductility have been well balanced because of the combination of multiple mechanisms. In the alloy with addition of 1at. % Al and 1 at. % Ti, the yield strength, tensile strength and elongation are 543.5 MPa, 854.2 MPa and 31.8 % respectively, which are increased by 110.2 %, 35.5 % and 70.1 % compared with Fe50Mn30Co10Cr10 alloy without Al-Ti addition. •Fe50Mn30Co10Cr10 metastable high-entropy alloys contenting Al-Ti elements were formed by selective laser melting.•The grain size in the alloys was negatively correlated with the content of Al-Ti elements•With the increase of Al-Ti elements content, the TRIP effect was gradually suppressed during plastic deformation.•L12 phase was precipitated in the alloys with Al-Ti elements.•The addition of Al-Ti significantly improves the strength and ductility of SLM-ed metastable high-entropy alloy.