Martensite is a very hard form of steel crystalline structure. It is named after German metallurgist Adolf Martens . By analogy the term can also refer to any crystal structure that is formed by diffusionless transformation .

1999年12月15日 · The evaluation of strengthening in these alloys has been limited to interpreting yield strength of unaged, untempered martensite in terms of interstitial solid solution strengthening. The second section reviews strengthening of martensitic Fe–C alloys and low-alloy carbon steels with above-room-temperature M s temperatures.

untempered martensite have been written by Cohen [3–5] and Owen [6], but because of the high mobility of carbon, the explanations developed have been based on experiments in iron–nickel–carbon alloys where carbon diffusion can be suppressed because of subzero Ms temperatures. Christian [7] has also reviewed the

The residual phase is untempered martensite which etches lighter because of the absence of carbide precipitates. It is follows that it is easy, using optical microscopy, to distinguish bainite and martensite as long as both phases are presente in the microstructure.

Untempered martensite. Untempered martensite is a strong, hard, brittle material. The stronger and harder it is, the more brittle it is. The strength and hardness is a due to elastic strains within the martensite, a result of too many carbon atoms being in …

2014年1月22日 · The hardness of untempered martensite depends almost solely on carbon content, but the influence of carbon on the hardness of tempered martensite decreases markedly as the tempering temperature is increased.

2023年7月1日 · The higher strength of RT420 compared to CT420 can be attributed to the total amount of strengthening boundaries, amount of fully tempered martensite and the presence of untempered martensite. The RT420 specimen exhibited a higher total amount of both high and low-angle boundaries, as evidenced by the results presented in Fig. 5 .

A complete mechanism of tempered martensite embrittlement is proposed involving i) precipitation of interlath cementite due to partial thermal decomposition of interlath films of retained austenite, and ii) subsequent deformation-induced transformation on

Iron-nickel-carbon alloys were selected to determine the role of carbon in the strengthening of virgin (untempered) martensite. The carbon content ranged from nil to almost 1 w/o C, while the nickel content was varied in the opposite sense to adjust the Ms temperature to -35° C.

During tempering, the particles coarsen and become large enough to crack, thus providing crack nuclei which may then propagate into the matrix. As a consequence, untempered low--carbon martensitic steels sometimes have a better toughness than when they are tempered, even though the untempered steel is stronger.