HIGH-PRESSURE PHASE-DIAGRAM AND VARIATION OF ELASTIC-MODULI OF AL-LI ALLOY

The high-pressure phase diagram of an Al-rich Al-Li alloy at a 5.4-GPa pressure was investigated. To determine the equilibrium state under high-pressure and high-temperature conditions, the quenching method was applied and a phase analysis of the sample was performed using X-ray diffraction and microscopic observations. The resultant solid solubility of lithium in aluminum was subsequently increased up to 20 at% and the eutectic temperature increased to 800-degrees-C. Then the material properties (mainly elastic moduli) for supersaturated solid solutions treated under high pressure were also investigated. The shear modulus of the solid solutions increased at the rate of 0.28 GPa/at%Li; in contrast, the bulk modulus decreased 0.52 GPa/at%Li.