Shear bands generally initiate strain softening and result in low ductility of metallic glasses. In this Letter, we report high-resolution electron microscope observations of shear bands in a ductile metallic glass. Strain softening caused by localized shearing was found to be effectively prevented by nanocrystallization that is in situ produced by plastic flow within the shear bands, leading t...

The structural complexity of soft gels is at the origin of a versatile mechanical response that allows for large deformation, controlled elastic recovery, and toughness in the same material. A limit to exploiting the potential of such materials is the insufficient fundamental understanding of the microstructural origin of the bulk mechanical properties. Here we investigate the role of the netwo...

Commercially pure nickel was processed by equal channel angular pressing (ECAP) through route Bc for 12 passes to obtain an ultrafine grained (UFG) microstructure and further subjected to an ultrasonic treatment (UST) which introduced a maximum amplitude equivalent to anormal stresses of 100 MPa in a steady state regime. It was observed that the microstructure of UFG Ni can be differently alter...

An elastic-viscoplastic constitutive material model is developed for the representation of creep response a 10%Cr steel under cyclic loading conditions. It has been shown that able to describe primary regeneration (PCR), i.e. incidence period high strain rate following stress reversal. The variant well-known Chaboche viscoplastic model, and employs bi-term power-law equation represent stress-re...

Age-hardening characteristics in a dental low-gold alloy composed of 40.0 wt% Au-35.0 wt% Ag-7.9 wt% Pd-7.0 wt% Cu-5.0 wt% In-3.5 wt% Zn-1.5 wt% Sn, were investigated by means of the hardness test, XRD study, SEM observations and EPMA. The following results were obtained. The age-hardening was characterized by a precipitation of Cu-rich alpha2 phase in the a phase. The softening that occurred f...

Dependence of mechanical properties of geomaterials on the variable chemical environment or advancement of chemical or mineralogical reactions is known to be a crucial factor in many cases of mechanical stability of geo-masses. Processes of mineral dissolution usually results in material weakening while precipitation of minerals such as of silica in aging or calcite in clay fractures may lead t...

Structural stability of a multiferroic compound CuFeO2 belonging to the delafossite family has been investigated at high pressures using in-situ Raman spectroscopy. At ambient conditions, CuFeO2 has a rhombohedral structure with space group R3m. It has two Raman active modes, identified as Eg and A1g. Both Raman mode frequencies harden with pressure. At 18 GPa, the doubly degenerate mode Eg spl...

Nonlinear oscillators with hardening and softening cubic Duffing nonlinearity are considered. Such classical conservative oscillators are known to have an amplitude-dependent period. In this work, we design oscillators with the Duffing-type restoring force but an amplitude-independent period. We present their Lagrangians, equations of motion, conservation laws, as well as solutions for motion.

The influence of thermomechanical deformation on the residual stresses caused by quenching in bar shaped specimens of heat treatable steel 42CrMo4 has been investigated using a mechanical method for detemining the distribution of residual stresses of the first kind. The results obtained show that the residual stress distribution after quenching is dected by the strengthening and softening of th...

We derive an effective medium theory that predicts the bulk and shear moduli of composite materials consisting of a matrix material with soft or hard ellipsoidal inclusions. The theory predicts that diskshaped inclusions are most effective for softening or hardening a composite material. The theory is applied to the design of materials with highly absorptive acoustical properties. DTIC TAB0 UJn...