Crystallography, martensitic transformation. Lecture 9 of 9

Crystallography of martensitic transformations, including the phenomenological theory
Associated teaching materials can be found on:
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H. K. D. H. Bhadeshia

[@FearNoSteel]

44:10 Titanium Carbide Martensitic transformation? Any more resources for this? I am curious about the hardness of Titanium Carbide versus Vanadium Carbide in high wear steels.

[@bhadeshia123]

There is only one paper on martensite in TiC, J. Am Ceram. Soc 78 (1995) 1537-1545. The Vickers hardness of TiC varies from 2500-3010 HV depending on crystallographic orientation (Journal of Materials Science 12 (1977) 595). That of polycrystalline vanadium carbide is 2500 HV (Journal of Physics and Chemistry of Solids. 69 (2008) 2465).

[@abhradeepdas2032]

Enlightening as usual.

[@bhadeshia123]

Thank you

[@puppysobti7311]

Sir one question - is the mechanism of nucleation i.e by fault mechanism and growth i.e by pole mechanism of martensite (as explained by olson and cohen in their paper) can be regarded as the best and acceptable mechanism of formation of martensite

[@bhadeshia123]

The fault mechanism is established by direct observation (Brooks et al.) for fcc-hcp. For fcc-bcc, the Olson and Cohen mechanism requires complex faulting and is not directly verified except in the sense that it predicts, as Magee had shown in 1970, that the activation energy for nucleation is proportional directly to the driving force.