Fatigue of Martensite-Ferrite High Strength Low-alloy Dual Phase Steels.

Abstract

As shown in Fig. 8(a The fracture surfaces of all the failed specimens were examined as shown in Fig. 12 (Fig. 12(a)). As shown in Fig, 12(b), the intermittent wetting by spraying tap water led to a large proportion of cleavage fracture. In contrast, transgranular cracking dominated the whole process of fracture when the specimens were fatigued in air ( Fig. l 2(c) (c) and (d) as-rolled specimen The magnification of (a) and (b) is the sameas that of (c The mechanical propertles are presented in Fig. 18

Investigation of small crack behaviour under cyclic loading in a dual phase steel with an FIB tomography technique

“…Each phase of this material has different mechanical properties i.e., the martensite has high strength but low ductility, whereas the ferrite phase has good ductility but low strength. Some researchers studied the effect of microstructure morphology on the fatigue behaviour of this material 12–15 . From surface observation, it was shown that cracks were initiated in a ferrite grain along slip bands and they propagated in the ferrite grains preferably because of the large difference in properties of each phase.…”

“…Some researchers studied the effect of microstructure morphology on the fatigue behaviour of this material. [12][13][14][15] From surface observation, it was shown that cracks were initiated in a ferrite grain along slip bands and they propagated in the ferrite grains preferably because of the large difference in properties of each phase. Very tortuous crack paths were formed because the martensite grains worked as a barrier against crack propagation.…”

A probabilistic two‐scale model for high‐cycle fatigue life predictions

“…It is based on the analysis of the thermal effects for the scatter and is applied on a dual-phase steel. This steel is used in the automotive industry that requires the knowledge of the fatigue properties and their scatter [17][18][19][20][21][22][23][24][25].…”

Evaluation of the Low‐Cycle Fatigue Life of Thin Dual‐Phase Steel Sheets for Automobiles Using Miniature Specimens

“…K is the material constant, which is about μ 100 À1 %μ 1000 À1 ; ε is true plastic strain; and n is the strain index coefficient, taken as 0.3. When the plastic strain amplitude is 0.5%, ρ S %3.0 Â 10 14 m À2 is obtained by combining Equation (4)- (6).…”