Influence of nitrogen on the microstructure and mechanical properties of Ti–48Al alloy

The influence of nitrogen on the microstructure and on the mechanical properties of a two-phase lamellar Ti–48Al alloy was studied. The prominent part played by nitrogen in influencing grain growth has been underlined. The effect of nitrogen, in solid solution in the α2 phase or in precipitates in the γ phase, on the microstructural parameters has been addressed. The studied mechanical properties (microhardness, compression yield stress and creep) are improved when the nitrogen content increases and when this element is in solid solution. This improvement is due to combined hardening factors such as the interlamellar spacing, the presence of nitrogen in solid solution or its precipitation. These factors are more or less effective, so the effects of each of them on the three kinds of studied mechanical properties have been specified.