BULK TITANIUM-RICH ALLOYS CONTAINING NANOSCALE DISORDERED REGIONS

Nanoscale disordered regions were obtained in titanium-rich alloys via annealing of a metastable crystalline phase. This metastable bcc soli d solution (beta) was formed in the alloy Ti65Cr13Cu16Mn4Fe2 following are melting and cooling or simply by air cooling a solutionized ingot . Since only air cooling was required to retain the beta phase, large ingots can be produced. During subsequent annealing, partial amorphiza tion occurred in conjunction with a phase transformation from beta to beta'. The premise for this amorphization is the reduction of the free energy difference between an amorphous phase and a metastable crystal line phase with proper alloy additions. Comparisons are made with amor phized powders at the same composition produced by mechanical milling.