“…Therefore, in principle, the thickness of the capsule should be minimized to reduce the cost of post-machining and waste material (Olevsky et al, 1996). On the other hand, it should have high degree of pressure tightness and maintain gas-leak-proof (Tsipunov et al, 1977) at the low and high pressures (typically up to 100 MPa) during evacuation, sealing, and densification as mentioned in Conway and Rizzo (1998). It should yield plastically under applied temperature and pressure conditions (Sears et al, 2002).…”