2000 Volume 86 Issue 7 Pages 492-498
Fatigue crack propagation behaviors of Ti-5Al-2.5Fe with various microstructure for biomedical use were investigated in air and a simulated body environment, Ringer's solution, in comparison with those of Ti-6Al-4V ELI and SUS 316L stainless steel.
The crack propagation rate, da/dN, of equiaxed α structure is nearly the same as that of Widmanstatten α structure in Ti-5Al-2.5Fe in air when da/dN is related to the nominal cyclic stress intensity factor range, ΔK. Ti-5Al-2.5Fe shows nearly same da/dN as Ti-6Al-4V ELI having equiaxed α structure, but shows a greater one than Widmanstatten α Ti-6Al-4V ELI. Without fine precipitated α, the da/dN of Ti-5Al-2.5Fe tested in air and in Paris regime is nearly equal to, but in threshold regime, greater than that of SUS 316L stainlsess steel. Fine precipitated α of Ti-5Al-2.5Fe tested in air makes the da/dN in threshold regime nearly equal to, but in Paris regime greater than that of SUS 316L.
When da/dN is related to ΔK, testing in Ringer's solution makes greater the da/dN of both Ti-5Al-2.5Fe and Ti-6Al-4V ELI than that obtained by testing in air. However, when da/dN is related to the effective cyclic stress intensity factor range, ΔKeff, the da/dN of both alloys is nearly the same in air and in Ringer's solution.
