On the heterogeneous nucleation of martensite
โ Scribed by H.Y. Yu; S.C. Sanday; B.B. Rath
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 444 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0921-5107
No coin nor oath required. For personal study only.
โฆ Synopsis
Martensitic nucleation near inhomogeneities is modeled using linear elasticity. The coherent strain energy due to the formation of a martensite embryo decreases when the inhomogeneity is elastically stiffer than the matrix and vice versa. A maximum reduction of 20% in strain energy is calculated for the case when the embryo is formed near a free surface. The results are consistent with the experimental observations of preferential nucleation of martensite at a free surface. A possible explanation for the nature of the "preexisting martensite embryo" in the Kaufman and Cohen model of a nucleation site is also proposed: the dislocation loop in the parent phase is itself the site for the embryo such that it will transform into martensite during transformation. The calculated critical characteristics of this embryo are in good agreement with the model of Chen and Chiao and their experimental results.
๐ SIMILAR VOLUMES
Abstmet-The heterogeneous nucleation of martensite at a dislocation is considered using an elasticity model. The dislocation is allowed to have an arbitrary Burgers vector representing, in an approximate manner, the stress field of a pile-up. It is found that an array of roughly 10 dislocations is r
The martensitic transformation in the following two model systems, Fe-30 at.% Ni and In-5.25 at.% Cd, was studied by X-ray diffraction and metallography in order to answer the following question: does the nucleation of martensites occur by a soft mode mechanism or by classical heterogeneous nucleati
Estimations of nucleation barriers for singledomain and multiple-domain states of a martensite phase have been obtained. A macroscopic approach, considering the free energy of a heterophase system to be a sum of the energy of the elastically stressed equilibrium phases and the energy of interfaces,