Effect of nitrogen addition on microstructures and mechanical propeties of TiAl based alloys

Through adding 0% similar to 3% (mole fraction) nitrogen in cast TiAl based alloys, it was found that colony size in cast condition decreased from 600 mu m to 58 mu m with nitrogen content increasing from zero to 1% and then decreased slowly with further increase of nitrogen content, tensile strength increased with nitrogen content; but comparing to the value of the mother alloy, tensile elongation at room temperature decreased in the alloy with 0.5% nitrogen, then recovered in the alloy with 1% nitrogen.