Amorphous interlayer assisted ductility of Mo-Cu alloy

Abstract

Generally, binary immiscible alloys have poor plasticity due to weak interfacial bonding. In this study, an amorphous interlayer was introduced between Mo and Cu phases in Mo-Cu alloys by using the high-temperature infiltration method. With the increase of infiltrated temperature from 1300 °C to 1450 °C, the thickness of the amorphous interlayer wad increased from 2 nm to 13 nm. The formation process, thermodynamic driving force, stability of the amorphous interlayer in Mo-Cu alloy, and its contribution to mechanical properties were systematically investigated. By using the “macroscopic atom approach” Miedema's model, the thermodynamic driving force and stability of the amorphous interlayer were proved. It was found that the thickening of the amorphous interlayer can significantly improve the interfacial bonding, thus leading to an increase in the tensile strength of the Mo-Cu alloy from 520 to 600 MPa and failure strain from 0.15 to 0.31 The deformation behavior of the Mo-Cu alloy shows that the amorphous interlayer can effectively absorb interfacial dislocations during deformation, and relieve the stress concentration at the interface by crystallization, thus delaying the initiation and propagation of cracks at phase boundaries, which broke through the limitation of the trade-off between strength and plasticity of such Mo-Cu immiscible materials.

Keywords

• Mo-Cu alloy
• Amorphous interlayer
• Macroscopic atom approach
• Stability
• Ductility