Properties and CA4GE-Engine Test of TiAl-Based Alloy Valves by Permanent Mold Casting
TiAl-based alloy valves were manufactured by combining charges compressed /vacuum arc melting (VA)/ induction skull melting (ISM) procedure with permanent mold centrifugal casting method. Microstructures, compositions and mechanical properties of as-cast and hot isostatical pressed (HIPed) valves are detected. Results show that the permanent mold centrifugal casting process obviously refines the size of grain in TiAl alloy and the tensile strength of as-cast and HIPed valves are 550MPa and 580MPa at 20°C, 370MPa and 470MPa at 815°C, respectively. As-cast specimens show ~0% elongation at 20°C and 1~2% at 815°C, while HIPed ones show an elongation of 1~2% at room temperature and about 10% at 815°C. Furthermore, a 200-hour test was carried out with CA4GE-engine, which demonstrated the possibility of as-cast TiAl alloy valves for the substitution of present steel ones.
Liangchi Zhang, Chunliang Zhang and Tielin Shi
W. B. Sheng et al., "Properties and CA4GE-Engine Test of TiAl-Based Alloy Valves by Permanent Mold Casting", Advanced Materials Research, Vols. 139-141, pp. 557-560, 2010