Structure and properties of cast binary Ti-Mo alloys

Area of Science:

• Materials Science
• Metallurgy
• Physical Chemistry

Background:

• Binary titanium-molybdenum (Ti-Mo) alloys are crucial in various industrial applications.
• Understanding the structure-property relationships in Ti-Mo alloys is essential for material design.
• Previous research has explored Ti-Mo alloys, but detailed investigations into the effects of specific molybdenum concentrations on mechanical properties are ongoing.

Purpose of the Study:

• To investigate the structure and properties of binary Ti-Mo alloys with varying molybdenum content (6-20 wt%).
• To determine the influence of molybdenum concentration on the crystal structure, morphology, hardness, bending strength, and bending modulus of Ti-Mo alloys.
• To identify optimal alloy compositions for specific mechanical performance characteristics.

Main Methods:

• Synthesis and characterization of binary Ti-Mo alloys with molybdenum content from 6 to 20 wt%.
• Experimental analysis of crystal structure and morphology using techniques such as X-ray diffraction and microscopy.
• Mechanical testing, including hardness measurements, bending strength, and bending modulus evaluation.

Main Results:

• Alloy crystal structure and morphology were found to be sensitive to molybdenum content.
• A hexagonal alpha' phase was observed in pure titanium (c.p. Ti) with a feather-like morphology.
• At 6 wt% Mo, a fine, acicular martensitic alpha" phase was observed. At 7.5 wt% Mo, the alloy was dominated by the alpha" phase. At 10 wt% Mo and higher, the retained beta phase became dominant.
• The alpha" phase Ti-7.5Mo alloy exhibited the lowest hardness among the investigated alloys.
• Ti-7.5Mo showed comparable bending strength to Ti-15Mo and Ti-13Nb-13Zr, and a 60% increase over c.p. Ti.
• The bending modulus of Ti-7.5Mo was lower than Ti-15Mo, Ti-6Al-4V, Ti-13Nb-13Zr, and c.p. Ti.

Conclusions:

• Molybdenum content critically dictates the phase structure and mechanical properties of binary Ti-Mo alloys.
• The Ti-7.5Mo alloy, characterized by its dominant alpha" martensitic structure, presents a unique combination of properties, including reduced hardness and enhanced bending strength.
• The findings provide valuable insights for tailoring Ti-Mo alloy compositions for applications requiring specific mechanical performance, such as biocompatible implants or high-strength structural components.