The Influence of the Alloy Microstructure on the Oxidation Behavior of Ti–46Al–1Cr–0.2Si Alloy

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• 作者：P&eacute ; rez ; P. ; Jim&eacute ; nez ; J. A. ; Frommeyer ; G. ; Adeva ; P.
• 关键词：TiAl ; based intermetallic alloy ; oxidation ; microstructure
• 刊名：Oxidation of Metals
• 出版年：2000
• 出版时间：2000
• 年：2000
• 卷：53
• 期：1/2
• 页码：99-124
• 全文大小：450 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Inorganic Chemistry
  Tribology, Corrosion and Coatings
  Metallic Materials
  
• 出版者：Springer Netherlands
• ISSN：1573-4889

文摘

The influence of microstructure of the two-phase alloyTi–46Al–1Cr–0.2Si on the oxidation behavior in air between600 and 900°C was studied. The oxidation rate, type of scale, and scalespallation resistance were strongly affected by the type of microstructure,i.e., lamellar in as-cast material and duplex after extrusion at1300°C. The oxidation rate was affected by the size and distribution ofthe $\backslash a$lpha_2-Ti_3Al phase, being faster for the extrudedmaterial with coarse $\backslash a$lpha_2-Ti_3Al. The type of oxide scaledetermines the spalling resistance. Cast material developed a uniform scalethat spalled off after short exposure times at 800 and 900°C when a criticalthickness was reached. The extruded material presented a heterogeneous scalewith predominant thick regions formed on $\backslash gamma-TiA$l-\alpha_2-Ti_3Algrains and thin scale regions formed on $\backslash gamma-TiA$l grains. Thistype of scale could permit an easier relaxation in the matrix of stressesgenerated by both thermal-expansion mismatch between scale and alloy andoxide growth, resulting in a higher spallation resistance.