Electropulsed steels

Philosophical Magazine Letters

2015

Oriented sulphides parallel to the electric current direction have been experimentally observed when a pulsed electric current is passed through medium carbon steels with MnS inclusions. Two different configurations of sulphides occur after the application of the electric current: namely, oriented elongated ellipsoidal particles and oriented chain-like particles composed of two or three small spherical sulphides. Theoretical analysis indicates that this phenomenon is associated with minimisation of the electrical resistance of the material.

Section: Introductionmentioning

confidence: 99%

Oriented sulphides induced by electric current in medium carbon steel

Zhang

Philosophical Magazine Letters

2015

“…The matrix is with a composition of Fe-7.78Ni-24.13Cr-6.57Mo (at.%). When the electric current is applied to the alloy at the high temperature annealing, the precipitates dissolve [10]. …”

Section: Validation Against the Analytical Theory And Experimental Obmentioning

confidence: 99%

Computational thermodynamics in electric current metallurgy

Materials Science and Technology

Bhowmik

2015

Self Cite

A priori derivation for the extra free energy caused by the passing electric current in metal is presented. The analytical expression and its discrete format in support of the numerical calculation of thermodynamics in electric current metallurgy have been developed. This enables the calculation of electric current distribution, current-induced temperature distribution and free energy sequence of various phase transitions in multiphase materials.The work is particularly suitable for the study of magnetic materials that contains various magnetic phases. The latter has not been considered in literature. The method has been validated against the analytical solution of current distribution and experimental observation of microstructure evolution. It provides a basis for the design, prediction and implementation of the electric current metallurgy. The applicability of the theory is discussed in the derivations.

“…4(a) is close to value of that for -carbide, but that in Fig. 4(b) is close to that of  phase [30,33]. The experimental measured values are consented to the theoretical analysis.…”

Section: Discussionmentioning

confidence: 99%

“…Schematic diagrams illustrate that the electrical resistivity of a material with microstructure (a) is larger than that of (b) when the grey phase has larger conductivity than that of the matrix. The figure was drawn following the similar concept in literature [30,33]. Matthiessen's theory, the electrical resistivity of -carbide is higher than that of  phase due to higher C, Al and Mn compositions in  than in .…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of κ-carbide interface structure on the formability of lightweight steels

2016

Materials & Design

Abstractκ-carbide () in high aluminium (Al) steels is grown from austenite () via + or α+ ( represents ferrite), and is a lamellar structure. This work demonstrates that the formability of high Al lightweight steels is affected by the lattice misfit and interface shape between  and matrix. The cold workability can be improved by either to change the steel chemical constitution or to implement an electro-thermo-mechanical process. For ferrite-matrix-based high Al steel, electric-current promotes the spheroidization and refinement of  structure and reduces volume fraction of  phase. This retards the crack nucleation and propagation, and hence improves the materials formability. The observation is caused by a direct effect of electric-current rather than side effects.