The morphology of martensite in iron alloys

Micromechanical modeling of dual phase steels

“…Interestingly, a Hall-Petch slope that was steeper was found in the as quenched martensite than that observed in carbon free martensite i.e: the yield strength of as-quenched Fe-C martensite increased much more rapidly with decreasing packet size than did that of carbon-free martensite. The effect of martensite packet size has also been reported by Roberts (1970), Marder and Krauss (1970), Krauss and Marder (1971) and Swarr and Krauss (1976) to have an influence on the ultimate and yield strength of the martensite. They have shown that this effect is important in the as quenched martensite but minor in the quenched and tempered martensite.…”

The Morphology of Thin Plate-Like Martensite in Fe–Ni–C Alloys

“…7 and the thin plate-like martensites shown in Photo. 1, optical micrographic observation was made in the same specimen area of Fe-33.5%Ni-0.22%C alloy which was strained with a progressive increase in 8 From these micrographs shown above, it is considered that many thin plate-like martensites with the same variant combine together and consequently become a thick plate martensite. Therefore, the thick martensite contains the parallel faint boundaries which are the boundaries of the former thin plate-like martensites.…”

Apparent Morphologies of Coarse Plate Martensite

“…[1][2][3][4][5][6][7][8][9] But the authors have found that coarse martensite plates also may appear as equilateral triangular morphologies, as shown in Fig. 4 and Fig.…”

“…It is universally accepted that the distribution of martensitic plates is random and cannot be parallel to each other [1][2][3] or not shows packet structure, [3][4][5] while lath martensite can merely exhibit packet-like, or equilateral triangular, or equilateral hexagonal structure. [6][7][8][9] Therefore, the widely prevailing criterion identifying the type of martensite under optical microscope is that the packet or equilateral triangular martensite is lath martensite.…”

“…[6][7][8][9] Therefore, the widely prevailing criterion identifying the type of martensite under optical microscope is that the packet or equilateral triangular martensite is lath martensite. [1][2][3][4][5][6][7][8][9] Recently, the authors [10][11][12][13] have studied in depth on the apparent morphologies of fine plate martensite in medium and high carbon steels, and found that when austenitizing temperature is higher, the chemical composition is homogenized, grains are coarsened and crystal defects are diminished, which in turn reduces the obstruction to directional nucleation and growth of martensite, fine plate martensite will become a regular arrangement, appearing as packetlike or equilateral triangular morphologies. Such martensites in medium and high carbon steels were named as Fibre Martensite 10,11) or Packet Plate Martensite by the authors.…”