High-temperature tensile properties of an aluminum quasicrystal-forming alloy manufactured by laser powder bed fusion

Abstract

Normalized tensile samples of Al–4Fe–3Cr–2Ti (wt.%) alloy were successfully fabricated by laser powder bed fusion (LPBF) additive manufacturing. The alloy's tensile properties and microstructure were investigated at room and high-temperature (up to 500 °C). This Al–Fe–Cr–Ti alloy exhibits exceptional thermal stability and outstanding mechanical performance at temperatures of up to 500 °C. A particularly interesting feature is the alloy's yield strength values, which reach ∼300 MPa at 300 °C and ∼180 MPa at 400 °C. The outstanding mechanical behavior of this alloy at high temperatures is attributed to the in situ precipitation of ultrafine icosahedral quasicrystalline (i-QC) particles endowed with high thermal stability. These values are notably higher than those achieved for A319, 6061-T6 and Al-8%wt.Cu–Mg–Ag cast alloys – three of the most common heat-resistant Al alloys, and higher than commercially available Al-based alloys for LPBF. Based on hardness measurements and the bimodal composite microstructure, we propose a model to predict this alloy's yield strength. This model shows a good agreement with the experimental results and can be used to maximize the alloy's tensile strength. This work describes a lightweight aluminum alloy with outstanding high temperature tensile strength within a wide range of temperatures, in addition to being additively processable and affordable.