Strength Tests of a CFRP Spar Using Methods of Acoustic Emission and Tensometry

Results of the strength tests of an aircraft wing spar made of Toray T1000 carbon fiber-reinforced plastic are presented. Construction failure zones have been inspected by the methods of acoustic emission (AE) and tensometry. Loading-induced changes in the stress-strain state (SSS) of wing-spar material have been analyzed. The coordinates of AE signal sources that correspond to the separation of the upper spar cap from the spar web have been determined. Algorithms for AE-data processing using wavelet transforms are considered. Connections have been established between changes in stresses emerging in CFRP material, AE signal structure, and the occurrence and propagation of spar fracture.     

Thermodynamic analysis of the characteristics of producer gas upon the gasification of Moscow brown coal

The thermodynamic calculation of the temperature dependence of the equilibrium composition of the products of the steam-air gasification of Moscow brown coal with the following proximate analysis data was performed at the pressure P = 0.1 MPa: C ^r = 31, H ^r = 2.3, N ^r = 0.6, O ^r = 9.6, S ₁ ^r = 2.7, A ^r = 20.8%, and W ^r = 33%. The temperature dependence of the concentrations of gas-phase components was plotted for the gasification of 100 g of Moscow coal on a dry ash-free basis at the blast coefficient α = 0.3 with steam supply (4 mol of H₂O). It was found that, in this case, the gas phase mainly consisted of N₂, CO, and H₂ at a temperature higher than 800°C. The energy characteristics of the gas phase were calculated.     

Structure and Properties of Surface Layers Obtained Via Nonvacuum Electron-Beam Cladding with Copper and Boron Powder Mixtures

Metallurgist - Powder mixtures containing copper, boron, and iron were deposited on flat steel billets via nonvacuum electron-beam cladding to form surface layers of increased thickness. The...     

Effect of deformation and heat treatment on the structure,the mechanical properties,and the fracture characteristics of an ultrafine-grained Zr–1Nb alloy

The effect of cold working and annealing for various times on the structure, the mechanical properties, and the fracture characteristics of an ultrafine-grained Zr–1 wt % Nb alloy after three-dimensional pressing is studied. Possible causes for increasing the thermal stability of the strength properties of the ultrafine-grained Zr–1 wt % Nb alloy during prerecrystallization annealing after additional cold working by rolling are discussed.     

Erratum to: Evolution of Dislocation Structure in a Ni3Al Single Crystal Under the Conditions of High-Temperature Superplasticity

Metal Science and Heat Treatment -     

Magnetic Properties and the Giant Magnetoimpedance of Amorphous Co-Based Wires with a Carbon Coating

A comparative analysis of the magnetic properties and specific features of the giant magnetoimpedance has been carried out for amorphous rapidly quenched wires with a composition of (Co_0.94Fe_0.06)_72.5Si_12.5B₁₅ in the initial state and after the deposition of a carbon coating. The deposition of the defective graphene-like carbon layer was carried out under normal conditions during the exposure in toluene (methylbenzene). The method of the energy-dispersive X-ray spectroscopy made it possible to reliably show that after the modification in toluene, the carbon content on the surface significantly exceeds the natural amount of carbon. The deposition of the carbon coating induced changes in the distribution of the initial quenching stresses in the near-surface layer of amorphous wires. A comparative analysis of the magnetic and magnetoimpedance properties of the samples before and after exposure in the aromatic solvent confirms the occurrence of changes in the effective magnetic anisotropy as a result of this surface treatment.     

Nanocrystalline erbium oxide powders synthesized by the solid-state method from carbonates, oxalates, and hydroxides

Nanocrystalline erbium oxide powders are synthesized by the solid-state method from carbonates, oxalates, and hydroxides. Depending on the prehistory of their preparation, the average particle size decreases in the series: oxalates > carbonates > hydroxides; being 10 to 20 nm at a thermal treatment temperature of 680°C