Plastic response and deformation microstructures in rhenium
- Michigan Technological Univ., Houghton, MI (United States)
Rhenium (Re) is a refractory metal with a hexagonal close packed (h.c.p.) crystal structure. It has several useful engineering properties such as high modulus of elasticity, good ductility and good wear resistance. It is virtually immune to thermal shock and is inert in most oxygen free atmospheres. Re has found applications in heat exchangers for solar rocket thrust nozzles and is also used as an alloying element in superalloys for production of single crystal turbine blades for jet engines. In spite of its increasing use, little is known about its plastic response, mechanisms of deformation and associated microstructural changes. Two kinds of polycrystalline Re produced by PM and CVD processes are used in this study. The PM Re is also cold rolled to achieve 50% and 80% reduction in thicknesses to enhance its mechanical properties. The constitutive response of the above four types of rhenium is investigated at a range of strain rates under uniaxial compression. The stress-strain response revealed a strong strain rate dependent yield stress followed by a high rate of work hardening, The plastic response was also found to depend on the amount of prior cold work. All the specimens deformed under uniaxial compression exhibited shear banding after attaining a critical strain, irrespective of the strain rate employed in this study. Multiple shear bands were noticed in several specimens. Void nucleation, growth and coalescence are identified as the major mechanisms responsible for the observed fracture along the shear bands. The deformed microstructures in these specimens were characterized by extensive twinning and grain boundary cracking.
- OSTI ID:
- 175302
- Report Number(s):
- CONF-950686--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Plastic deformation of hafnium under uniaxial compression
Examining deformation localization of irradiated tungsten under uniaxial compression with crystal plasticity