Diffusion behavior of Mn and Al in refractory elements alloyed TiAl-based intermetallic compound with high-throughput diffusion multiple approach

To investigate the effects of alloying elements on the diffusion behavior of Mn and Al in TiAl alloys, a series of diffusion couples were prepared using a high-throughput diffusion multiple approach. The couples, which included Ti42Al5Mn–M (where M denotes 0, 0.8W, 0.8Mo, 2Nb, and 2Zr, at. %), Ti42Al, and Ti54Al, were aged at 1000 °C for 1000 hours. The phase composition of the annealed samples and the concentration profiles of Al and Mn across the diffusion zones were systematically characterized by electron probe microanalysis (EPMA). Based on these profiles, the diffusion distances of Al and Mn were measured, and their interdiffusion coefficients in TiAl alloys containing W, Mo, Nb, or Zr were calculated according to Fick’s second law. The influence of these alloying elements on the diffusion behavior of Mn and Al was comprehensively analyzed and discussed.