Structural and Mechanical Characteristics of Cu50Zr43Al₇ Bulk Metallic Glass Fabricated by Selective Laser Melting.

Xiaoyang Lu,Wenhe Liao,Mussokulov Nursulton,Yulei Du

doi:10.3390/ma12050775

Abstract

In this work, the structural and mechanical characteristics of Cu50Zr43Al7 bulk metallic glass (BMG) fabricated by selective laser melting (SLM) are studied and the impacts from the SLM process are clarified. Cu50Zr43Al7 alloy specimens were manufactured by the SLM method from corresponding gas-atomized amorphous powders. The as-built specimens were examined in terms of phase structure, morphologies, thermal properties and mechanical behavior. The x-ray diffraction and differential scanning calorimetry results showed that structural relaxation and partial crystallization co-exist in the as-fabricated Cu50Zr43Al7 glassy samples. The nano- and micro- hardness and the elastic modulus of the SLM-fabricated Cu50Zr43Al7 BMG were higher than CuZrAl ternary BMGs with similar compositions prepared by conventional mold casting, which can be attributed to the structural relaxation in the former sample. However, the macro compressive strength of the SLM-fabricated Cu50Zr43Al7 BMG was only 1044 MPa mainly due to its porosity. This work suggests that the SLM process induced changes in structural and mechanical properties are significant and cannot be neglected in the fabrication of BMGs.

Highlights

Bulk metallic glasses (BMGs) are promising structural materials because of their unique mechanical, physical and chemical properties [1,2,3]
The hardness and elastic modulus of the Selective laser melting (SLM)-fabricated Cu50 Zr43 Al7 BMGs were much higher than those of the CuZrAl ternary BMGs prepared by conventional mold casting
In addition to the densely packed layers, a number of pores were found in the solidified molten pool boundaries of the local zones on the SLM-fabricated BMG sample, which may be the main reason for the low relative density of the SLM-fabricated Cu50 Zr43 Al7 BMG

Summary

Introduction

Bulk metallic glasses (BMGs) are promising structural materials because of their unique mechanical, physical and chemical properties [1,2,3] Due to their limited ability to form glass, it is difficult to fabricate BMGs with large cross sections or complex shapes by traditional mold casting methods. Selective laser melting (SLM), a laser additive manufacturing technique, can obtain a cooling rate as high as 103 –104 K/s during the point-by-point and layer-by-layer forming period. It can realize the freeform fabrication of metallic materials and has recently been adopted in various attempts to produce BMGs [6]. The application of SLM and infrared lasering in the manufacturing Cu-based BMGs is restricted by the high thermal conductivity and the high reflectivity of Cu-based alloys, resulting in greater heat loss and an inadequate melting of the powders during the SLM process

Methods

Results

Conclusion