Fe-based bulk metallic glasses (BMGs) have attracted great attention due to their unique magnetic and mechanical properties, but few applications have been materialized because of their brittleness at room temperature. Here we report a new Fe₅₀Ni₃₀P₁₃C₇ BMG which exhibits unprecedented compressive plasticity (>20%) at room temperature without final fracture. The mechanism of unprecedented plasticity for this new Fe-based BMG was also investigated. It was discovered that the ductile Fe₅₀Ni₃₀P₁₃C₇ BMG is composed of unique clusters mainly linked by less directional metal-metal bonds which are inclined to accommodate shear strain and absorbed energy in the front of crack tip. This conclusion was further verified by the X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy experiments of Fe_80-xNi_xP₁₃C₇ (x = 0, 10, 20, 30) and Fe_72-xNi_xB₂₀Si₄Nb₄ (x = 0, 7.2, 14.4, 21.6, 28.8) glassy systems. The results also indicate a strong correlation between the p-d hybridization and plasticity, verifying that the transition from brittle to ductile induced by Ni addition is due to the change of bonding characteristics in atomic configurations. Thus, we can design the plasticity of Fe-based BMGs and open up a new possible pathway for manufacturing BMGs with high strength and plasticity.

As a promising additive manufacturing technique, selective laser melting (SLM) provides the possibility of fabricating metallic glassy components free of the constraints of geometrical complexity and dimensions. However, unexpected crystallization greatly affects the microstructure and degrades the mechanical performance of SLM-fabricated metallic glasses (MGs). To clarify the crystallization mechanism and the effect of laser processing on the crystallization, we investigate the atomic-level crystallization in the SLM Zr₉₀Cu₁₀ MG by using molecular dynamics simulations. The results show that crystallization highly related to scan speed lies in the atomic-level cluster changes. Lower scan speed leads to a dramatically increased fraction of the BCC crystal phase, accompanied by the nucleation of a few HCP and FCC crystal phases. As scan speed increases, more icosahedron-like clusters are formed, leading to the formation of the MG, while the nucleation of the crystal phase is suppressed. The suppression of crystallization is further attributed to a higher average temperature variation rate induced by higher scan speed, which reduces the relaxation time, preventing the nucleation and growth of crystal phases. This work contributes to the understanding of the crystallization in MGs during the SLM process at the atomic level, providing guidance to suppress the crystallization in the SLM process of desired metallic glassy components.