Laser processing of a CuTiZr-based alloy by powder bed fusion: From bulk metallic glass to metallic glass composite

Additive manufacturing of bulk metallic glasses using laser powder bed fusion is a challenging task, even for materials with a high glass-forming ability. This is due to the complex thermal history of the additively manufactured glass-forming materials, which are repeatedly heated upon laser processing of subsequent layers, leading to their devitrification. In this study, the influence of laser processing on the commercial Cu-based metallic glass AMLOY-CU01, having a reduced glass transition temperature T rg ∼0.44, has been systematically explored, incorporating high-energy synchrotron X-ray diffraction studies complemented by transmission electron microscopy. Despite the low T rg , both vitrified and devitrified states can be obtained. The findings reveal that phase composition is weakly correlated with porosity in the keyhole regime but shows a strong correlation in the lack of fusion regime. The stabilization of the nearly glassy state of the metallic glass is achieved within a laser energy density range of 11 J mm −3 ≤ e ≤ 25 J mm −3 and a normalized enthalpy range of 92 ≤ Δ H ≤ 239, correlating with moderate porosity values in the obtained samples. The current results provide insights into the fundamental understanding of phase formation in glass-forming materials synthesized by laser processing and pave the way for their engineering application. • The different phase composition can be controlled through the process conditions. • The thermal history determines the phase formation in the glass-forming alloy. • The porosity contributes to the stabilization of crystalline phases near the pores.