Journal ArticleDOI
Roles of dislocations and grain boundaries in martensite nucleation
TLDR
In this article, the role of dislocations and grain boundaries in martensite nucleation was investigated and the authors concluded that grain boundaries provide nucleation site, but only certain types of grain boundaries are qualified to be potential nuclei.Abstract:
In order to elucidate roles of dislocations and grain boundaries in martensite nucleation, the transformation temperature (Ms) of specimens austenitized at various temperatures and subjected to prestrain has been measured, using Fe-Ni, Fe-Ni-C, and Fe-Cr-C alloys. It is concluded that the plastic accommodation, in austenite, of the shape strain of the transforming martensite is a vital step in the nucleation event. Any factors impeding such plastic accommodation, such as the lack of dislocations, work hardening, and grain refinement, suppress the transformation. Contrary to the general belief, dislocations themselves do not act as favorable nucleation sites. Grain boundaries provide nucleation site, but only certain types of grain boundaries are qualified to be potential nuclei. A quantitative analysis shows that the increasing difficulty for the plastic accommodation with decreasing grain size is the main factor to depress Ms in fine-grained specimens.read more
Citations
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Journal ArticleDOI
Young’s modulus and mechanical properties of Ti-29Nb-13Ta-4.6Zr in relation to α″ martensite
Y. L. Hao,Rong Yang,Mitsuo Niinomi,Daisuke Kuroda,Y. L. Zhou,Keiichi Fukunaga,Akihiro Suzuki +6 more
TL;DR: In this paper, the formation of α″ martensite and its influence on Young's modulus and mechanical properties of forged Ti-29Nb-13Ta-4.6Zr (wt pct) alloy is reported.
Journal ArticleDOI
3D structural and atomic-scale analysis of lath martensite: Effect of the transformation sequence
TL;DR: In this article, a multi-probe methodology is developed and applied to low-carbon lath martensitic model alloys to improve the fundamental understanding of the multi-scale characteristics of microstructures and their micro-mechanical properties, which is based on the joint employment of electron channeling contrast imaging (ECCI), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), atom probe tomography (APT), in conjunction with high precision and large field-of-view 3D serial sectioning.
Journal ArticleDOI
Aging response of the young’s modulus and mechanical properties of Ti-29Nb-13Ta-4.6Zr for biomedical applications
Y. L. Hao,Ruijuan Yang,Mitsuo Niinomi,Daisuke Kuroda,Y. L. Zhou,Keiichi Fukunaga,Akihiro Suzuki +6 more
TL;DR: In this article, a metastable β-type titanium alloy, Ti-29Nb-13Ta-4.6Zr (wt pct), was subjected to aging treatment to produce different microstructures, and the resulting mechanical properties including the Young's modulus were measured.
Journal ArticleDOI
Effect of microstructure variations on the formation of deformation-induced martensite and associated tensile properties in a β metastable Ti alloy
TL;DR: In this article, the effect of the microstructure on the activity of different deformation mechanisms and the resulting mechanical behavior of a metastable β Ti alloy (β-Cez) was investigated.
Journal ArticleDOI
Effect of β grain size on stress induced martensitic transformation in β solution treated Ti–10V–2Fe–3Al alloy
TL;DR: Grain size in β-solution treated Ti-10V-2Fe-3Al alloy has been shown to have a profound effect on the triggering stress of the stress induced martensitic (SIM) transformation as mentioned in this paper.
References
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Book
Theory of Dislocations
John Price Hirth,Jens Lothe +1 more
TL;DR: Dislocations in Isotropic Continua: Effects of Crystal Structure on Dislocations and Dislocation-Point-Defect Interactions at Finite temperatures.
Journal ArticleDOI
The Deformation and Ageing of Mild Steel: III Discussion of Results
TL;DR: In this paper, an attempt is made to explain the observed phenomena in the yielding and ageing of mild steel, described in two previous papers, in the general terms of a grain-boundary theory.
Journal ArticleDOI
The crystallography of martensite transformations II
J.S Bowles,J.K Mackenzie +1 more
TL;DR: In this paper, the total strain in a martensite transformation was derived from the orientation relationship and the component strains, together with the correspondence, and the dimensions of the initial and final structures.
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