Rotating bending fatigue tests on specimens with small cracks were carried out in order to investigate characteristics of threshold stress intensity factor range (ΔK_<th>) for magnesium alloys: AMX602B (X=Ca), AZX912D (X=Ca) and Mg-Ni6.4%-Y11.3% and carbon steel S10C. Obtained result are as follows. (1) ΔK_<th> of Ni6.4%-Y11.3% was a half of S10C though Mg-Ni6.4%-Y11.3% had the same Vickers hardness as S10C. (2) For dependence of crack size, ΔK_<th> of AMX602 and AZX912 increased with the crack size ranging from 150μm to 500μm. On the other hand, ΔK_<th> of Mg-Ni6.4%-Y11.3% had the constant value with the crack size ranging from 80μm to 350μm. (3) The stress intensity factor range at crack propagating lower limit (ΔK_p) from a pre-crack was 0.6MPa・m^<1/2> for magnesium alloys and 2.6MPa・m^<1/2> for S10C. It is likely that ΔK_<th> of magnesium alloys was lower than that of S10C owing to difference of ΔK_p. (4) The prediction equation for ΔK_<th> on magnesium alloys with a small crack was proposed. It can be easily to estimate ΔK_<th> within less than 20% eor using the proposed method.
|Translated title of the contribution||PS32 Characteristic of threshold stress intensity factor range for small crack on magnesium alloys|
|Number of pages||3|
|Publication status||Published - 2010|