Microstructure and Properties of Mechanical Alloying Al-Zr Coating by High Current Pulsed Electron Beam Irradiation

The “HOPE-I” type high-current pulsed electron beam (HCPEB) equipment was used to irradiate the pure aluminum material with Zr coating preset by ball milling to realize the alloying of a Zr–Al coating surface. The microstructure and phase analysis were conducted by XRD, SEM, and TEM. The experimental results show that after Zr alloying on the Al surface by HCPEB, a layer of 15 μm was formed on the surface of the sample, which was mainly composed of Zr and Al–Zr intermetallic compounds. A large number of Al3Zr (Ll2) particles was uniformly distributed in the alloyed layer, and the Al grains were obviously refined. In addition, the surface hardness and corrosion resistance of the samples were improved significantly after HCPEB irradiation.

Providing of Operational Properties for Gas-Turbine Engine Parts and Assemblies Using Electrospark Deposition

Article explains manufacturing capability of titanium parts reliability enhancement and life cycle enhancement by electrospark deposition using low energy discharges. Carbon electrodes used to form functional properties of parts surface layer. Alloyed carbooxide zone consist of highly dispersed structure (with particles of titanium carbide, titanium oxide, graphite), with 3-10 micron thick, and high hardness antifrictionality. Alloyed layer contain ordered phase Ti8C5, TiC, and the structure of Ti6C3,75. Parts dimensions almost do not changed after electrospark deposition with carbon electrodes. Subsequent diamond burnishing decrease friction coefficient and surface roughness. Fatigue resistance increased after healing of defects and microcracks. Local carbooxidation and burnishing used to increase wear resistance of titanium alloys.

Additive Influence of Carbon and Carbides of Vanadium and Chrome in Anodic Tungsten-Cobalt Materials on their Erosive Fragility and Formation of the Alloyed Layer at ESA of Steels 35

The effect of electric-spark deposition (ESD) on carbon steel 35 by functional-gradient electrode materials based on tungsten carbide with additions of chromium and vanadium carbides is shown. These dopants increase the total weight gain of the cathode and the mass transfer coefficient at ESD. The change of anode material erosion resistance parameters and roughness of alloyed layers using Ra, Rz, Rp, Rq, Tn parameters were studied. It is shown that an increase in the roughness parameters is observed with a decrease in the duty cycle and with an increase in the duration of the pulses in the period of the electric-spark discharge, as well as with an increase in the total gain of the cathode and with mass transfer coefficient. For the studied anode materials, an averaged series of increasing erosion resistance was obtained for ESA: M1→ BK15→ BK8→ M210% → M28%. and a series of increasing roughness parameters Ra, Rz, Rp, Rq, Tn: BK8→ BK15→ M28%→ M210%→ M1. With a long-term ESD up to t = 20 min, the dependence of the roughness parameter growth on the increase of ΣΔк, Кср and processing regimes and processing modes tsк, tр remains the same. It has been established that the addition of grain growth inhibitors 0.4Cr3C2 + 0.4VC and 0.4VC-0.4Cr3C2 + 0.4C to anodic W-Co materials significantly increases the total cathode weight ΣΔк, mass transfer coefficient Kp and the thickness of the alloyed layer in ESA steel 35, at the same time, the microhardness of the alloyed layer remains almost the same.

TRIBOLOGICAL BEHAVIOR OF Al–Cr COATING OBTAINED BY DGPSM AND IIP COMPOSITE TECHNOLOGY

An Al–Cr composite alloyed layer composed of an Al enriched layer, a Cr enriched layer and a transition layer from the surface to the bulk along the cross-section was deposited on a 45# steel substrate by composite technology, where Cr was deposited using double glow plasma surface metallurgy (DGPSM), and Al was then implanted by ion implantation (IIP) to achieve higher micro-hardness and excellent abrasive resistance. The composite alloyed layer is approximately 5[Formula: see text][Formula: see text]m, and as metallurgical adherence to the substrate. The phases are Al8Cr5, Fe2AlCr, Cr[Formula: see text]C6, Cr (Al) and Fe (Cr, Al) solid solution. The wear resistance tests were performed under various rotational speed (i.e. 280, 560 and 840[Formula: see text]r/min) with silicon nitride balls as the counterface material at ambient temperature. The Al–Cr composite alloyed layer exhibits excellent wear resistance when the speed is 280[Formula: see text]r/min with a friction coefficient as low as 0.3, which is attributed to Al8Cr5 in the Al implanted layer that withstands abrasive wear. Better wear resistance (friction coefficient: 0.254) at 560[Formula: see text]r/min is resulted from the formation of a high micro-hardness zone, and an oxidation layer with lubrication capacity. In addition, the composite alloyed layer suffers severe oxidative wear and adhesive wear at 840[Formula: see text]r/min due to the increment of the frictional heating. When compared to the 45# steel substrate, the enhanced wear resistance of the Al–Cr composite alloyed layer demonstrates the viable method developed in this work.