PISTON RING

摘要

Disclosed is a piston ring which can vary a tension under low-temperature and low-load conditions and a tension under high-temperature and high-load conditions, and therefore can minimize the friction loss and improve the fuel efficiency. The piston ring is formed by a titanium-tantalum shape memory alloy comprising tantalum in an amount of not less than 30 mol% and less than 40 mol%, with the remainder being titanium and unavoidable impurities.