Microstructure, mechanical properties, and high-temperature oxidation resistance of boronized {gamma}-TiAl(Mn)

Book · Wed Dec 31 04:00:00 EST 1997

OSTI ID:571734

Kim, S; Yoon, Y ^[1]; Kim, H ^[2]; Park, K ^[3]

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1. Inha Univ., Inchon (Korea, Republic of). Dept. of Metallurgical Engineering
2. Inha Technical Coll., Inchon (Korea, Republic of). Dept. of Metallurgical Engineering
3. Chung-ju National Univ., Chungbuk (Korea, Republic of). Dept. of Materials Engineering

Titanium aluminide (TiAl) based intermetallic compounds are considered as potential materials for high-performance automobile and aircraft engine components and airframe applications because of their low density (3.8 g/cm{sup 3}), high melting temperature (1,480 C), and good elevated temperature strength retention. To improve the wear and high-temperature oxidation resistance of reactively sintered {gamma}-TiAl(Mn) intermetallic compounds, they were boronized in the temperature range of 900 to 1,100 C for 5 to 11 hours with powder mixtures of B{sub 4}C and Na{sub 2}B{sub 4}O{sub 7}. It was found that the coating layer consisted of three sublayers, i.e., outer, middle, and inner sublayers. The outer, middle, and inner sublayers were identified as a mixture of TiB{sub 2} and TiO{sub 2}, a mixture of Al{sub 2}O{sub 3} and TiO{sub 2}, and Ti-rich TiAl based compounds, respectively. The coating layer significantly improved the surface hardness and the wear and high-temperature oxidation resistances. The highest surface hardness (Hv {approx} 2,720) was obtained at 900 C for 11 hours. This surface hardness is much higher than that of TiAl(Mn) (Hv {approx} 400). In addition, the specimens boronized at both 1,000 and 1,050 C for 9 hours showed an excellent high-temperature oxidation resistance. It is believed that the boronizing on the TiAl(Mn) intermetallics is very effective to improve the wear and high-temperature oxidation resistances.

• OSTI ID: 571734
• Report Number(s): CONF-961202--
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
36 MATERIALS SCIENCE
AEROSPACE INDUSTRY
ALUMINIUM ALLOYS
AUTOMOTIVE INDUSTRY
CORROSION RESISTANCE
EXPERIMENTAL DATA
INTERMETALLIC COMPOUNDS
MANGANESE ADDITIONS
MECHANICAL PROPERTIES
MICROSTRUCTURE
SURFACE TREATMENTS
TITANIUM ALLOYS
TITANIUM BORIDES
TITANIUM OXIDES