Evaluating Molybdenum-Rhenium Alloys Through Additive Manufacturing

Highly successful advanced manufacturing techniques of refractory metals are becoming increasingly necessary to navigate technology gaps. Refractory metal alloys are desirable to meet the need for high temperature structural materials, but are difficult to produce because of their high strength, low ductility, and high melting point. This work demonstrates the use of laser powder bed fusion to produce several Mo-Re alloys by additively manufacturing mechanically mixed pure elemental powders. Relationships are explored between mechanical properties regarding build orientation, laser speed, rhenium alloy content, and the addition of 3% hydrogen to the argon shield gas. Mechanical characterization was accomplished by three-point flexural testing. Rhenium content, hydrogen addition to the shield gas, and build orientation were all found to significantly affect the flexural strength. The build direction had the highest influence, and a maximum strength of 833.3 MPa was achieved in the vertical direction while the maximum strength in the horizontal direction was 346.1 MPa.