Dissolution of cementite in carbon steels by ball drop deformation and laser heating

Partially amorphous nanocomposite obtained from heavily deformed pearlitic steel

“…They assume that this ␥-Fe can absorb dissolved carbon [15]. After ball-drop deformation, ferrite grains become nanometer sized and featureless structures under SEM observation appear when cementite is completely dissolved [18]. This seems to be a strong evidence for the appearance of an amorphous phase, as is reported in this work.…”

“…An issue that should be discussed is the role of the deformation mechanism: mechanical milling (MM) [13,20], high-pressure torsion (HPT) [12,[15][16][17], equal channel angular pressing (ECAP) [19], as well as ball drop [18] experiments were performed with pearlitic steel. After mechanical milling, no cementite whatsoever was found in TEM and FIM/TAP [13,20].…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In this context, the dissociation of cementite upon plastic deformation has been discussed for some time [2][3][4][5]18,21,22]. Two mechanisms have been proposed so far: (i) the binding enthalpy between carbon atoms and dislocations in ferrite is higher than the binding enthalpy of carbon atoms to iron in ferrite [2,11], and (ii) the energy of the cementite/ferrite interface increases due to a Gibbs-Thomson effect and hence destabilizes cementite [4,8].…”

“…However, quite a few of these studies implied the complete dissolution of large proportions up to 100% of the initial cementite [4,8,9,12,[16][17][18]. In contrast, the local loss of cementite structure retaining a carbon concentration as high as about 10 at.% was also discussed [4,6].…”

Microstructure evolution of a hypereutectoid pearlite steel under rolling-sliding contact loading

“…Due to the practical importance of WEL, much effort has been made to simulate the microstructural evolution and WEL formation of pearlite steels using severe deformation processes (e.g. mechanical milling [1,2], surface mechanical attrition treatment [3,4] and high pressure torsion (HPT) [5]) and fast heating processes such as laser-treatment [6,7].…”