The yield stress of opposed anvils

The Lur’e solution for an elastic cone has been integrated to give a more reasonable solution of the state of stress of a Bridgman anvil. The maximum shear stress at the center axis is plotted as a function of the tapered angle. It shows that with a smaller tapered angle the anvil gives higher pressure before it plastically yields. It is estimated the maximum pressure can be achieved in a Drickamer-type apparatus with pistons made of maraging steel is around 85 kbar and that of cemented tungsten carbide is around 300 kbar. Based on published claims of achieved pressures, the maximum pressure capability of sintered-diamond compact is greater than 1.2 Mbar and that of a single-crystal diamond could possible be as high as 3.2 Mbar.