Martensitic Transformation in [110] Single Crystals of Cu-Al-Ni Alloy

Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 180 40 Praha 8, Czech Republic

Abstract

The martensitic transformations β₁(D03)↔γ'₁(2H), β₁ ↔ β'₁ (18R1) and γ'₁↔ β'₁ were investigated in the [110] oriented single crystals of Cu-14.3Al-4.1Ni (wt.%) alloy. Thermal cycling and deformation tests in tension and compression were performed to induce the transformation process. The experimental results were summarized in a non-equilibrium σ-T phase diagram (σ-T map) which exhibits single-phase regions β₁ and γ'₁ two-phase region β₁ + γ'₁and β'₁ + γ'₁ and three- phase regions β₁+ β'₁+ γ'₁ The tensile and compression parts of the σ-T map are not identical. This ”tension-compression asymmetry" is compared with similar asymmetry observed for other crystal orientations.