An effect of the second phase morphology on the tensile fracture characteristics of carbon steels

Effect of grain refinement to 1μm on strength and toughness of dual-phase steels

“…Kunio et al [56] introduced the idea that connected martensite is the site of the incipient cracks which trigger cleavage in the ferrite. According to Uggowitzer and Stüwe [57], the fractured martensite acts as a sharp notch, leading to cleavage in ferrite.…”

The unzipping model of fatigue crack growth and its application to a two-phase steel

“…If the applied stress is high enough, the nucleated cracks in the ferrite grains will propagate into the martensite and cause final fracture. Kunio et al [18,19] studied the micro-structural aspects of fatigue cracks in a martensitic-ferritic steel, and Miller [20] discussed the phenomenon of non-propagating fatigue crack in such a two-phase steel. The effects of the geometric arrangement of the ferrite and martensite grains on AKth and tensile yield strength were investigated [21,22].…”

Two Step Ductile to Brittle Transition Behavior on Ferrite + Pearlite Structure Steel Sheet

“…1) However, there is a limitation for the applications of high strength materials owing to their poor fracture properties. Several studies on the fracture behavior of DP steels have been conducted with particular focus on tensile, [2][3][4][5] fatigue, 5,6) and hydrogen embrittlement. 7,8) On the other hand, regarding the impact fracture, the influence of the volume fraction of martensite on the impact absorbed energy 9,10) has been evaluated along with the effect of tempering.…”