CHARACTERISTICS OF A METASTABLE H-2 TYPE PHASE IN A QUENCHED BETA-1 CU-AL-NI ALLOY

The structure of the metastable phase has been analyzed by taking into account the effect of ordering the transformation between the beta //1 matrix phase and the metastable 2H type phase is reversible and diffusionless in nature. The 2h type phase and the so-called ″mottled structure″ are present even in the martensitic phase. This is indication that the 2H type phase is not a premartensitic phase but a metastable phase which competes with the subsequent martensitic phase.