Y. Mae, Maetech, Saitama-city, Japan
The author proposed the thermal conductivity-Young's modulus diagram on which every solid element is plotted for the interpretation of alloying effects. Castability coefficient was defined as the freezing zone at 1 mol % addition of alloying elements for the evaluation of castability and weldability. Solution hardenability and quenching hardenability were defined as the strength increase at 1 mol % addition of alloying elements. Fe is located near the center of the diagram, and near the straight line of Fe connecting Ti, V, Ta, Cr, Mo and W, and is surrounded by many other elements. Therefore, Fe has many elements with small castability coefficients showing good castability and weldability. Castability coefficients of the elements near Fe are small and increase with increasing distance from Fe, especially toward the lower Young's modulus. Solution hardenability is small at the elements near Fe and increases with increasing distance concentrically from Fe and decreases again furthermore. Quenching hardenability is also small at the elements near Fe and increases with increasing distance from Fe only toward the upper part of the straight line of Fe. Toward the lower part of the straight line of Fe, quenching hardenability becomes negative. Ti is located at the lowest end of the straight line of Fe. Therefore, castability coefficients of the elements on the straight line of Fe and in the region of low Young's modulus are small. Solution hardenabilty is small near Ti and in the low Young's modulus region and increases toward the higher Young's modulus region along the straight line of Fe. From these results, in general, alloying elements in the higher Young's modulus and higher thermal conductivity region than the matrix metal are desired, but in many cases, elements in such regions are very seldom. In such cases, intermetallic compounds would be useful.
Summary: The author proposed the thermal conductivity-Young's modulus diagram for the interpretation of alloying effects. In general, alloying elements in the higher Young's modulus and higher thermal conductivity region are desired, but in many cases, elements in such regions are very seldom. In such cases, intermetallic compounds would be useful.
