Fracture behaviour of a TiAl alloy under various loading modes

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

“…4. This alloy was extruded and solution treated to have lamellar microstructures and used in earlier studies [5,9]. The wrought alloy has a random lamellar interface trace distribution since the alpha grains were formed during solution treatment of worked materials through recrystallisation.…”

Brittle Fracture of TiAl Alloys and NiTi Memory Alloys

“…This type of fracture was found in tensile test, 3PB test, and tensile fatigue test of FL4 TiAl alloys with higher strength. The dimensions of specimens made of a special Ti-44Al-4Nb-5Hf-0.2Si-1B are the same as shown in Figure 9.2a, c, and d (Cao, Lin, et al, 2008). Figure 9.18 shows the curves of global tensile tests of Alloy FL4.…”

“…For the tensile tests, the measured ultimate normal strength is around 600 MPa for the FL microstructure, which is much higher than the local yield strength in soft orientation of 100 MPa. Thus, it could not be ruled out that before Two modes of fracture of global specimen of TiAl alloy: (a) and (b) critical crack-triggered fracture, and (c) damage accumulation-induced fracture (Cao, Lei, et al, 2007;Cao, Lin, et al, 2008).…”

“…Curves plotting applied stresses against strains measured in tensile tests of FL4 TiAl alloy (Cao, Lin, et al, 2008). Figure 9.20 shows the results of 3PB global tests and the fracture surface of a 3PB-tested specimen of FL4 TiAl alloy with a slit notch.…”

“…This figure convincingly identifies the model of critical crack-triggered fracture in the TiAl alloy with higher strength. Fracture surface of tensile fatigue specimen FL4-TF-202 (white arrow points to the critical cracking region) (Cao, Lin, et al, 2008).…”