Metallographic Atlas of Titanium and Titanium Alloys
Metallographic Atlas of Titanium and Titanium Alloys--II
Ti-3Al-2. 5V(Ti Gr.9) Titanium Alloy
Ti-3Al-2.5V(Ti Gr.9) Titanium alloy is nearly α titanium alloy (Chinese brand TA18). The alloy, developed in the United States, is a medium strength titanium alloy between pure titanium and Ti-6Al-4V(Ti Gr.5) titanium alloy. Its characteristic is much better than Ti-6Al-4V(Ti Gr.5) titanium alloy cold processing, suitable for cold rolling into tubes, sheets, and other products. Its phase transition point is 935℃. The mechanical properties of the alloy are shown in Table 2-1, and the microstructure is shown in Picture 2-1~ 2-6.
Table 2-1 Mechanical Properties of Ti-3Al-2.5V(Ti Gr.9) Titanium Alloy pipes (730℃/1h air cooling)
Test Temperature (℃) | Tensile Strength (Rm/MPa) | Yield Strength (Rp0.2/MPa) | Enlongation (%) |
Room Temperature | 692 | 568 | 20 |
150 ℃ | 552 | 457 | 18 |
200 ℃ | 513 | 427 | 23 |
250 ℃ | 475 | 400 | 24 |
300 ℃ | 459 | 392 | 25 |
Picture 2-1: After 950℃ water quenching for 30min, Ti-3Al-2.5V(Ti Gr.9) Titanium alloy has
β-transformed structure completely, and there are large α-sheets (bright) in the crystal.
Picture 2-2: after water quenching treatment at 920℃/30min, The equiaxed primary
α (bright) + lamellar β transformation structure (dark) of Ti-3Al-2.5V(Ti Gr.9) Titanium alloy
Picture 2-3: Ti-3Al-2.5V(Ti Gr.9) titanium alloy after 900℃/30min water quenching treatment,
Equiaxed primary α (bright) + lamellar β transformation tissue (dark)
Picture 2-4: Ti-3Al-2.5V(Ti Gr.9) titanium alloy after 800℃/30min water quenching treatment,
Incomplete recrystallized structure, equiaxed α+ intercrystalline β
Picture 2-5: Cold rolled Ti-3Al-2.5V(Ti Gr.9) titanium alloy tubes were treated at 700℃/60min,
Vacuum annealing treatment (longitudinal) elongated α+ intergranular β
Picture 2-6: Cold rolled Ti-3Al-2.5V(Ti Gr.9) titanium alloy tubes were treated by vacuum annealing at 800℃/60min (longitudinal),
Equiaxed α+ intergranular β+ annealing twins