Decades of research has been focused on improving the high-temperature properties of nickel-based superalloys, an essential class of materials used in the hot section of jet turbine engines, allowing increased engine efficiency and reduced CO2 emissions. Here we introduce a new 'phase-transformation strengthening' mechanism that resists high-temperature creep deformation in nickel-based superal...

This work investigated phase change mechanisms during excimer laser ablation of nickel specimens. Time-resolved measurements were carried out to determine optical properties and the velocity of the laser-ablated plume, the ablation rate per pulse, light scattering from the laser-ablated particles and the size of the laser-ablated particles, in the laser fluence range y2 y2 Ž y2 y2 . between 2.5...

Mechanical properties of machined components are controlled by inducing phase transformations in the outer layer of the materials. Induction hardening is one such manufacturing process where the surface hardness is enhanced while the core is retained with the original structure and characteristics. In this study, a mathematical model had been developed to predict the hardness and the volume fra...

The preparation of nano-sized TiO2 by titanium tetraisopropoxide (Ti(OiPr)4) via sol-gelmethod using acid as a catalyst is investigated and the optimized conditions concerning theproportional amount of acid, water, alcohol is established by XRD and SEM. The effect ofcalcination temperature on phase transformation of TiO2 (rutile, anatase and brookite) wasdetermined by XRD. The smallest grain si...

Simultaneous thermal analysis (STA) method has been applied to study decomposition reactions of AP under a flowing nitrogen atmosphere and static air. Results obtained indicate that a phase transformation occurs prior to the decomposition reaction. Decomposition takes place exothermally in two stages, first stage of decomposition could be suppressed by the controlled heating programme. Addi...

A fully physically-based thermodynamic and kinetic model of the β ↔ δ phase transformation in energetic crystal HMX crystal embedded in polymeric binder is developed. It is based on a new nucleation mechanism via melt mediated nano-cluster transformation and the recently formulated growth mechanism via internal stress-induced virtual melting. During the nucleation, nano-sized clusters of β phas...

Dielectric relaxation spectra of a metastable crystal phase formed on implosive and exothermic transformation of pressure-amorphized hexagonal ice have been measured in situ at 0.97 GPa pressure over a range of temperature. The metastable phase showed no relaxation peak at 130 K and 0.97 GPa. When heated at a fixed pressure of 0.97 GPa, it began to transform at approximately 145 K exothermally ...

Structural characteristics of phase transformations in epitaxial ferroelectric films are analyzed via a Landau–Devonshire thermodynamic formalism. It is shown that the phase transformation temperature, the lattice parameters, and the order of the phase transformation are a strong function of the misfit strain and are considerably different compared to unconstrained, unstressed single crystals o...