Tensile Deformation Behaviors of CuNi Alloy Processed by Equal Channel Angular Pressing

Abstract

The microstructure of the CuNi alloy specimen ER is mainly elongated coarse grains. However, the microstructure of the specimen EH is inhomogeneous and some recrystallized sub‐grains form. In addition, the misorientation angles of the specimens ER and EH are mainly smaller than 15°, showing a feature of low‐angle grain boundaries. Although the uniform elongation of the ECAPed CuNi alloy decreases rapidly, the yield strength of the CuNi alloy is improved more than three times after ECAP for one pass. The mechanical properties, deformation, and fracture of CuNi alloy are not significantly affected by the strain rates. With the increase in strain rates, the yield strength of the specimen E0 hardly changes but the ultimate tensile strength increases slightly. However, with the increase in strain rates, the tensile strength of the specimen EH gradually improved. Besides, the fracture fractographies of the specimens EH turn into shear dimples at high strain rate. In addition, both the strain‐hardening exponent n and strain‐rate sensitivity m of the specimens EH are small, inducing lower strain‐hardening, uniform plastic deformation and resistance to the shear deformation.

Size-Dependent Brittle-to-Ductile Transition in Silica Glass Nanofibers

“…High strain rate can promote the room-temperature strength and tensile ductility of both crystalline and amorphous materials. − However, in our experiments, the ductility of SiO 2 nanofibers show a reversed behavior, that is improved ductility under low strain rate, though their strengths follow the similar trend as other materials. The abnormal strain-rate dependence of the ductility of SiO 2 nanofibers can be attributed to its unique deformation mechanism of “surface diffusion”. , The plastic flow of SiO 2 nanofibers is mainly mediated by the surface-plasticized region, in which bond changes occur frequently and result in the annihilation of cavities or crack-nuclei that were generated by the deformation.…”

Ultrafine-Grained Precipitation Hardened Copper Alloys by Swaging or Accumulative Roll Bonding

“…Common methods for generating ultra fine grained metals by Severe Plastic Deformation (SPD), such as Equal Channel Angular Pressing (ECAP) or Accumulative Roll Bonding (ARB) [5][6][7], are well known and established, especially for pure copper. In contrast to SPD-related studies on pure copper, the archival literature sources dealing with severe plastic deformation of copper alloys are significantly more rare [8,9].…”