Thermal Expansion of the T1 (Al2CuLi) Intermetallic Phase in a V-1480 (Al–Cu–Li) Alloy

Abstract—The linear thermal expansion coefficients (LTECs) of the α solid solution and the T1 (Al2CuLi) intermetallic phase in a V-1480 (Al–Cu–Li) alloy are determined by X-ray diffraction in the temperature range 100–500°C. The fcc α solid solution is found to have an LTEC of 26.2 × 10–6 K–1, and the hcp T1 phase has an LTEC of 20.1 × 10–6 K–1 along the a axis and 5.2 × 10–6 K–1 along the c axis. T1 phase particles have an unusual platelike shape. They are nearly two orders of magnitude thicker than they are wide. This is attributed to the high anisotropy of the interatomic bonding forces, which is reflected in the fourfold difference between the LTEC values. The LTEC values are measured in the basal plane and along the c axis of the hcp lattice of this phase.