Solidus curve of the Al–Cu alloy system under pressure

The mean-square displacement of thermal vibrations and melting for the Al and Al–Cu alloy system are studied using our previous treatment based on microscopic electronic theory. The temperature- and concentration-dependent mean-square displacement for Al1−xCux system decreases under pressure. The Debye temperature obtained at low temperatures for Al1−xCux solid solution decreases as a function of the Cu atomic fraction x, but increases at higher temperatures. The effect of pressure on the solidus curve is discussed by applying Lindemanʹs melting law to the alloy system, and the phase diagram of Al–Cu alloy system under pressure is predicted theoretically.