反応焼結による新しいAl-Ti-N系合金の作製(第5報) -Cu添加によるL1_2構造のAl_3Ti相の生成- A New Ternary Al-Ti-N Alloy Prepared by Reaction Sintering(V)-Formation of L1_2-Al_3Ti Phase by the Addition of Cu
The mechanism of the crystal structure transformation of Al<SUB>3</SUB>Ti from DO<SUB>22</SUB> to a high symmetry Ll<SUB>2</SUB> by the addition of Cu was investigated using the DV-X α molecular orbital calculation. The calculation suggested that Ti atoms were able to locate at the 2nd neighbor sites of Ti atoms by substitution of Cu atoms for a part of Al atoms, namely, the 1st neighbor sites of Ti atoms. This atomic configuration is the mechanism for the stabilization of the Ll<SUB>2</SUB> crystal structure of Al<SUB>3</SUB>Ti by the addition of Cu. Therefore, Cu was added to improve the ductility of a new reaction sintered Al-Ti-N alloy which consists of Al<SUB>3</SUB>Ti and AlN phases. The added Cu transformed the crystal structure of Al<SUB>3</SUB>Ti from DO<SUB>22</SUB> to a high symmetry Ll<SUB>2</SUB>, and as a result, decreased the hardness of the alloy.
粉体および粉末冶金 43(4), 533-539, 1996-04-15
Japan Society of Powder and Powder Metallurgy