Microstructure and tensile properties of cast Ti-44Al-4Nb-4Hf-0.1Si-0.1B alloy with refined lamellar microstructures

Numerical investigation of room-temperature deformation behavior of a duplex type γTiAl alloy using a multi-scale modeling approach

“…Previous works showed that improvement of certain desirable properties, e.g., stiffness and strength, reduces the ductility of the alloy to some extent, and well balanced properties with respect to strength and ductility are not yet obtained in a satisfactory manner [1][2][3]. Today, knowledge of the alloy chemistry and processing techniques has been greatly improved, promoting the development of new-generation TiAl alloys.…”

A Quarter Century Journey of Boron as a Grain Refiner in TiAl Alloys

“…The crack in the microzone could be larger than the critical crack size for propagation. This hypothesis was supported by the observation of clusters of parallel facets from interlamellar cracking of fine lamellar colonies on the fracture surfaces and also by the fact that the ductility of Ti45A15NblMo0.2B was improved to 1% after forging and heat treatment which has certainly destroyed the phase transformation texture [51][52][53].…”

“…Ti44A18Nb0.1B, Ti44A14Nb4HfO. 1B and Ti45A15NblMo0.2B [51][52][53]. In those alloys the lamellar colony size was not more than lOO^m.…”

“…However, the room temperature tensile ductility of the as-cast low boron containing alloys was much lower than expected, being only 0.3-0.5% despite the fine grain size and fine boride precipitate size. The ductility loss in low boron containing beta solidifying TiAl alloys was attributed to the phase transformation texture [51]. It was pointed out in section 4.1 that the grain refinement in this type of alloys was through boride assisted alpha nucleation during beta-to-alpha solid phase transformation.…”

Microstructure and mechanical properties of low and heavy alloyed γ-TiAl + α2-Ti3Al based alloys subjected to different treatments

“…Alloys Ti-47Al-1.5Cr-2Nb [2] Ti46Al-8Ta [14] Tie46Ale8Nb [14] Ti-43Al-4Nb-1Mo-0.1B [22] Ti-44Al-4Nb-4Hf-0.1Si-0.1B [26] Ti-43.7Al-3.2(Nb,Cr,Mo)-0.2B e this work d, % …”