Sulfur bearing Ti-based bulk metallic glasses for the Laser Powder Bed Fusion of metals

大块金属玻璃(BMG)的添加制造是最近出现的一种可行的方法。特别是激光粉末床熔合(PBF-LB/M)技术被认为是一种很有前途的技术，可以克服制备BMG在尺寸和复杂性方面的限制。与晶态合金相比，BMG具有非常大的弹性极限，约为2 %，并具有高强度和高硬度。它们的性质特征使它们成为高压力应用中破坏性材料替代的潜在候选者。最近发现的含硫TiZrCuS合金具有很高的耐腐蚀性，强度几乎是Ti6Al4V的两倍。然而，它们的小临界铸件厚度约为1 mm，处于大块金属玻璃(1 mm或更大)定义的边缘。这有效地使该合金的传统铸造工艺失去了作为一种功能生产路线的资格，适用于广泛的应用。然而，TiZrCuS合金在低温过冷液相区具有良好的抗结晶热稳定性。然而，大量的氧杂质和有限的热历史知识对PBF-LB/M过程中的非晶玻璃化过程提出了挑战。在这个问题上，本项目旨在研究Ti60Zr15Cu17S8在PBF-LB/M过程中激光与材料的相互作用。将通过高速成像、比热法和有限元模拟来彻底研究激光-材料相互作用过程中的热分布和历史，以考虑所产生的所制造样品的热力学、结构和工艺特性。

Additive manufacturing of bulk metallic glasses (BMGs) has recently emerged as a viable method. Especially laser powder bed fusion (PBF-LB/M) was established as a promising technique to overcome the limitations in size and complexity during the fabrication of BMGs. In comparison to crystalline alloys, BMGs feature exceptional large elastic limits of about 2 % combined with high strength and hardness. Their properties profile renders them as potential candidates for disruptive material substitutions in highly stressed applications. The recently discovered sulfur-bearing TiZrCuS alloys offer high corrosion resistance and almost twice the strength of Ti6Al4V. However, their small critical casting thickness of about 1 mm is on the edge of the definition of a bulk metallic glass (1 mm or more). This effectively disqualifies conventional casting processes of this alloy as a functional production route for a broad spectrum of applications. Yet, TiZrCuS alloys feature a respectable thermal stability against crystallization in the low-temperature supercooled liquid region. This makes the system robust against crystallization under cyclic thermal exposure, as present during PBF-LB/M. However, large amounts of oxygen impurities and limited knowledge about the thermal history challenge the amorphous vitrification during PBF-LB/M. In this matter, the project aims to investigate the laser-material interaction during PBF-LB/M processing of Ti60Zr15Cu17S8. A thorough investigation of the thermal profiles and history during the transient laser-material interaction via high-speed imaging, ratio-pyrometry, and FEM simulations will be conducted in view of the resulting thermodynamic, structural, and technological properties of the manufactured samples.