Structural transformations in alloys of the 36NKhTYu type containing molybdenum

Conclusions

• 1. In alloys of the 36NKhTYu type containing molybdenum the decomposition of the solid solution during tempering (aging) with precipitation of the main strengthening phase (γ′-phase) is uniform through the whole volume, while in the 36NKhTYu alloy not containing molybdenum the precipitation of the phase begins at the grain boundaries.

• 2. The addition of 5 and 8% Mo to the 36NKhTYu alloy leads to the following results: a) Theγ-solid solution is strengthened because about 4% molybdenum is dissolved in it; b) the resistance of the main strengthening phase, (Ni, Fe)₃(Ti, Al, Mo) to coagulation and to transformation into the hexagonal Ni₃Ti phase increases and a second strengthening phase of the Fe₂Mo type is created.

  The composition of the molybdenum phase varies with the quenching temperature and the aging temperature.

• 1. The presence of the strengthened solid solution and of two strengthening phases (γ′-phase with 150–300 A particles and the Fe₂Mo phase with plates of 0.1 μ to several microns) in alloys containing molybdenum after quenching and tempering results in high hardness and high elasticity.