Elastic properties of hot-isostatically-pressed magnesium diboride

Magnesium diboride was hot-isostatically pressed using three qualitatively different cycles: dense material cooled under pressure (DMCUP), “standard” cycle with pressure and temperature simultaneously reduced, and isothermal pressure release. Elastic properties of dense MgB2 were measured at normal conditions using resonant ultrasound spectroscopy method. The highest values of elastic moduli correspond to the sample processed using DMCUP cycle. The data for fully dense samples are in satisfactory agreement with theoretical predictions based on quantum mechanics calculations. The effect of lower density on elastic constants is consistent with a theoretical approach based on elasticity theory taking into account effect of porosity.