Strain glass transition in a multifunctional β-type Ti alloy

Area of Science:

• Materials Science
• Condensed Matter Physics
• Alloy Development

Background:

• GUM metals (multifunctional Ti alloys) show superior mechanical properties and unique physical effects like Invar and Elinvar.
• The origins of Invar and Elinvar effects in GUM metals remain unexplained, as typical structural or magnetic transitions are absent.

Purpose of the Study:

• To elucidate the fundamental mechanism behind the Invar and Elinvar effects in GUM metals.
• To investigate the role of structural transitions in the physical properties of Ti-23Nb-0.7Ta-2Zr-1.2O (at%) alloy.

Main Methods:

• Analysis of a typical GUM metal: Ti-23Nb-0.7Ta-2Zr-1.2O (at%) alloy.
• Investigating the phenomenon of strain glass transition.
• Examining the influence of random point defects and cold rolling on nano-domain structure and texture.

Main Results:

• The GUM metal undergoes a strain glass transition, characterized by martensitic nano-domains freezing over a wide temperature range due to point defects.
• Cold rolling induces a strong texture in these nano-domains, leading to lattice elongation and the Invar effect upon cooling.
• The nano-domain structure of the strain glass also explains the Elinvar effect and low modulus observed in these alloys.

Conclusions:

• The strain glass transition provides a unified explanation for the Invar effect, Elinvar effect, and low modulus in GUM metals.
• This finding advances the fundamental understanding of the physical properties of GUM metals and related alloys.
• The study highlights the importance of nano-domain structure and strain glass phenomena in advanced materials.