Influence of Ti addition on the microstructure and comprehensive properties of Mo–Cu alloy

Abstract

To enhance the overall performance of Mo–Cu alloy, Ti was added to Mo–Cu alloy to improve the bonding strength of Mo/Cu interface and generate solid solution strengthening effect. The outstanding performances of Mo–Cu–Ti alloys were achieved by infiltrating Cu–Ti alloy with different compositions into the Mo skeleton. Compared to the incoherent interface of Mo/Cu in Mo–Cu alloy, the addition of Ti transformed its interface to the coherent interface of Mo–Ti/Cu–Ti. All Mo–Cu–Ti alloy blocks had higher relative densities (97.4%∼98.5%) to guarantee the excellent comprehensive performances. What's more, the existences of Mo–Ti and Cu–Ti solid solutions assured the alloy possessed relatively high mechanical strength. The introduction of Ti purified the grain boundary by absorbing oxygen to generate TiO2 which hindered the growth of Mo–Ti grains. As increasing Ti amount from 0 wt% to 4.62 wt%, the Mo–Ti (or Mo) grain size reduced from 5 μm to 4.1 μm. Notably, Mo–Cu alloy block with the addition of 2.30 wt% Ti possessed the highest tensile strength of 562 MPa. Additionally, since the finer grain size of Mo–Ti alloy, this sample also owned the maximum micro-hardness and bending strength of 268 HV and 1730 MPa, respectively. Nevertheless, the presences of Cu–Ti solid solution and TiO2 also destroyed the electrical conductivities of the samples to some extent.

Keywords

• Solution strengthening
• Grain boundaries
• Phase interface
• Fine-grain strengthening
• Dispersion strengthening