Abstract
In the present work, the mechanism of martensitic transformation, the influence of γ-Fe particle size on the martensitic transformation induced by cold working, and the transformation of γ-Fe into α-Fe by thermal treatment alone in a Cu-1.5 at% Fe alloy, was studied using field ion microscopy (FIM) and transmission electron microscopy (TEM). It has been found that γ-Fe precipitates smaller than about 10 nm did not transform martensitically to α-Fe by cold working. Precipitates larger than 10 nm adopted a Kurdjumov-Sachs orientation relationship with the copper matrix; and the martensitically transformed α-Fe precipitates were ellipsoidal in shape, with their major axes being oriented parallel to the 〈1 1 0〉 direction in the matrix. Dislocations were found in the matrix near the vicinity of transformed α-Fe precipitates, giving support to the dislocation cutting mechanism proposed by other workers for the transformation. In thermally aged alloys, no transformation of γ-Fe to α-Fe was observed during the coarsening of γ-Fe precipitates up to sizes as large as about 50 nm. These precipitates still remained coherent or semi-coherent with the copper matrix.
Original language | English |
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Pages (from-to) | 4802-4807 |
Number of pages | 6 |
Journal | Journal of Materials Science |
Volume | 29 |
Issue number | 18 |
DOIs | |
State | Published - Jan 1994 |
Externally published | Yes |