Dynamic Tensile Characterization of Hiperco 50A Alloy at Various Strain Rates and Temperatures.

Soft ferromagnetic alloys are often utilized in electromagnetic applications due to their desirable magnetic properties. In support of these applications, the ferromagnetic alloys are also desired to bear mechanical load at various environmental temperatures. In this study, a Permendur 2V alloy manufactured by Metalwerks Inc. (but referred to Hiperco 50A, a trademark of Carpenter Technologies Inc.) was dynamically characterized in tension with a Kolsky tension bar and a Dropkinson bar at various strain rates and temperatures. Dynamic tensile stress-strain curves of the Hiperco 50A alloy were obtained at the strain rates ranging from 40 to 230 s -1 and temperatures from -100 to 100degC. All tensile stress-strain curves exhibited an initial linear elastic response to an upper yield followed by a Eiders banding response and then a nearly linear work-hardening behavior. The yield strength of this material was found to be sensitive to both strain rate and temperature; whereas, the hardening rate was independent of strain rate or temperature. The Hiperco 50A alloy exhibited a feature of brittle fracture in tension under dynamic loading with no necking being observed. ACKNOWLEDGEMENTS The authors acknowledge Kyle Johnson, Jefferey Dab ling, Donald Susan, Jay Carroll, Adam Brink, Scott Grutzik, and Andrew Kustas for the valuable discussion of test plan and results. Thanks Donald Susan for specimen preparation for this project. The authors also thanks Randy Everett for his support to the operation of dynamic tests in this proj ect.