TY - JOUR

T1 - Influence of High-Current-Density Impulses on the Compression Behavior

T2 - Experiments with Iron and a Nickel-Based Alloy

AU - Demler, E.

AU - Gerstein, G.

AU - Dalinger, A.

AU - Epishin, A.

AU - Rodman, D.

AU - Nürnberger, F.

N1 - Funding information: Financial support for this work provided by the German Science Foundation (DFG) under Contract GE 2673/2-1.

PY - 2016/12/8

Y1 - 2016/12/8

N2 - Difficulties of processing of high strength and/or brittle materials by plastic deformation, e.g., by forging, require to develop new industrial technologies. In particular, the feasible deformation rates are limited for low-ductile metallic materials. For this reason, processes were investigated to improve the deformability in which electrical impulses are to be applied to lower the yield strength. However, owing to the impulse duration and low current densities, concomitant effects always occur, e.g., as a result of Joule heating. Current developments in power electronics allow now to transmit high currents as short pulses. By reducing the impulse duration and increasing the current density, the plasticity of metallic materials can be correspondingly increased. Using the examples of polycrystalline iron and a single-crystal, nickel-based alloy (PWA 1480), current advances in the development of methods for forming materials by means of high-current-density impulses are demonstrated. For this purpose, appropriate specimens were loaded in compression and, using novel testing equipment, subjected to a current strength of 10 kA with an impulse duration of 2 ms. For a pre-defined strain, the test results show a significant decrease in the compressive stress during the compression test and a significant change in the dislocation distribution following the current impulse treatment.

AB - Difficulties of processing of high strength and/or brittle materials by plastic deformation, e.g., by forging, require to develop new industrial technologies. In particular, the feasible deformation rates are limited for low-ductile metallic materials. For this reason, processes were investigated to improve the deformability in which electrical impulses are to be applied to lower the yield strength. However, owing to the impulse duration and low current densities, concomitant effects always occur, e.g., as a result of Joule heating. Current developments in power electronics allow now to transmit high currents as short pulses. By reducing the impulse duration and increasing the current density, the plasticity of metallic materials can be correspondingly increased. Using the examples of polycrystalline iron and a single-crystal, nickel-based alloy (PWA 1480), current advances in the development of methods for forming materials by means of high-current-density impulses are demonstrated. For this purpose, appropriate specimens were loaded in compression and, using novel testing equipment, subjected to a current strength of 10 kA with an impulse duration of 2 ms. For a pre-defined strain, the test results show a significant decrease in the compressive stress during the compression test and a significant change in the dislocation distribution following the current impulse treatment.

KW - current impulse

KW - high current density

KW - nickel alloy

KW - plasticity

KW - pure iron

UR - http://www.scopus.com/inward/record.url?scp=85001575159&partnerID=8YFLogxK

U2 - 10.1007/s11665-016-2457-x

DO - 10.1007/s11665-016-2457-x

M3 - Article

AN - SCOPUS:85001575159

VL - 26

SP - 177

EP - 184

JO - Journal of Materials Engineering and Performance

JF - Journal of Materials Engineering and Performance

SN - 1059-9495

IS - 1

ER -