Strain-controlled fatigue properties of dissimilar welded joints between Ti–6Al–4V and Ti17 alloys

Cyclic Deformation Behavior of a Rare-Earth Containing Extruded Magnesium Alloy: Effect of Heat Treatment

“…[1]). [79] In comparison with the as-extruded alloy, the absolute values of b and c in both T5 and T6 states were higher, but the values of r 0 f and r 0 f were higher as well. As a result, a coupled role of these fatigue-life prediction parameters listed in Table II would give an equivalent lifetime of the GW103K alloy in different states within the experimental scatter, as shown in Figure 9, [17] which was in general longer than that of RE-free extruded Mg alloys.…”

“…In general, a smaller absolute value of fatigue strength exponent (b) and fatigue ductility exponent (c) and a larger value of fatigue strength coefficient (r 0 f ) and fatigue ductility coefficient (e 0 f ) reflect a longer fatigue life. [79][80][81][82] This indeed implies that a longer fatigue life of a material in the strain-controlled fatigue tests requires a good combination of both higher strength and superior ductility. In spite of such a seemingly conflicting effect of the exponent pair (b and c) and the coefficient pair (r 0 f and e 0 f ) on the fatigue life, the exponent pair would be expected to play a more significant role in the sense of exponential functions (Eq.…”

“…Since each fatigue striation could be assumed to roughly represent a single loading cycle, the spacing of fatigue striations could reflect the fatigue crack propagation rate and the associated fatigue life. [79] It is known that the occurrence of fatigue striations was due to a repeated plastic blunting-sharpening process in face-centered cubic (fcc) materials arising from the slip of dislocations in the plastic zone in front of the fatigue crack tip. [83] The formation of the fatigue striations in the HCP Mg alloy was anticipated to be related to both dislocation slip and twinning in the plastic zone during fatigue crack propagation.…”

Tensile and fatigue behavior of electron beam welded dissimilar joints of Ti–6Al–4V and IMI834 titanium alloys

“…The hysteresis loops at different cycles of dissimilar joint were basically symmetrical (Fig.8) in spite of the hexagonal close-packed crystal structure of the titanium alloys, unlike those of extruded magnesium alloys [39][40][41][42]. Symmetrical hysteresis loops in titanium alloys were also reported in [22,43,44]. Fig.9 shows the effect of total strain amplitudes on the shape of hysteresis loops at the mid-life cycle.…”

“…Casavola et al [14] reported the effect of material and welding process on fatigue strength of laser and hybrid welded titanium alloy joints. While limited studies on the strain-controlled fatigue behavior of a few dissimilar titanium alloy joints were reported in [20][21][22][23][24], no such fatigue behavior of the dissimilar joints between Ti-6Al-4V and IMI834 (Ti-6Al-5Sn-2Zr-1Mo-0.35Si-1Nd) alloys has been reported so far. It is unknown how big the effect of the welding on the microstructure, hardness, tensile and strain-controlled fatigue properties would be in the dissimilar joints between Ti-6Al-4V and IMI834 alloys.…”