The orientation relationship (OR) between MX-type alloy carbides and α- or γ- iron has been predicted based on the elastic strain energy theory and studied by means of high-resolution transmission electron microscopy (HRTEM). The elastic strain energy theory predicted that VC, TiC and NbC hold the Baker-Nutting OR (B-N OR) with the body-centered-cubic (bcc) αFe while they do not adopt a cube-on-cube OR with the face-centered-cubic (fee) γFe. HRTEM observation of TiC precipitation in a 0.05C-0.20Ti-2.0Ni steel showed that TiC precipitate obeys the B-N OR with martensite in the samples tempered at 600 and 800°C, in good agreement with the prediction. However, precise measurement of lattice rotation using moiré pattern in addition to diffraction analysis indicated that deviation up to 5° from the exact B-N OR is common. TiC precipitates forming in austenite at high temperatures deviate significantly from the B-N OR and they are essentially incoherent with their martensite matrix which is produced by γ-α transformation during quenching. It was found by thermal desorption spectrometry (TDS) analysis that the coherency of TiC precipitate plays a very important role in hydrogen trapping with respect to hydrogen capacity, interaction energy with hydrogen and the trap site of hydrogen.
|Number of pages||12|
|Publication status||Published - Dec 1 2005|
|Event||International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2005 - Phoenix, AZ, United States|
Duration: May 29 2005 → Jun 3 2005
|Other||International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2005|
|Period||5/29/05 → 6/3/05|
All Science Journal Classification (ASJC) codes