Equal channel angular pressing of wire-formed Al6063 by PU rubber-assisted procedure

Expanding suitable severe plastic deformation processes seems essential to design lightweight wire-formed materials for emerging demands. In this regard, 6063 aluminum alloy in the form of wire was processed successfully by polyurethane rubber assisted-equal channel angular pressing up to 16 passes by route BC. It was found that significant improvement of hardness and strength is achieved at the initial passes due to the increment of material’s dislocations density which leads to the crystallite size decrease and lattice microstrain increase. Also, subsequent passes improve the mechanical properties with a gentle rate due to the saturation of dislocation strengthening. The fractography analysis indicated that the ductile fracture mode of the annealed aluminum decreases by imposing the ECAP process. It is related to the formation of cleavage and rive patterns and the reduction in the number and size of the dimples compared to the initial condition. Eventually, X-ray diffraction findings showed that by adding pass numbers, the isotropy degree of the aluminum sample enhances because of the lowest diffraction scattering.

EXPERIMENTAL INVESTIGATION ON THE EFFECTS OF SURFACE MECHANICAL ATTRITION TREATMENT ON THE SURFACE OF THE ALUMINUM ALLOY

Surface mechanical attrition treatment (SMAT) or ultrasonic shot peening method improves mechanical properties of metallic materials by causing the plastic deformation on their surface layer of the workpiece. In this research, an ultrasonic generator, an ultrasonic booster, a sonotrode, one hundred steel balls with the mean diameter of 1 mm, an optical microscope, an automatic roughness meter, and other supporting accessories are employed to conduct the experiment. The effect of shot peening time of the ultrasonic shot peening method on the surface coverage and the roughness of the treated aluminum sample A7075 is systematically investigated. The study reveals that shot peening time has a significant effect on the coverage and the surface roughness of the treated samples. The surface of sample is rougher with the increasing of shot peening time and the surface is full coverage after shot peening in 35s. The results of this study indicate that the method of surface mechanical attrition (SMAT) or ultrasonic shot peening is an effective method to induce the plastic deformation on the material. It also shows that this is a promising method to investigate the effects of experimental parameters on the microstructure, properties, and fatigue life of the material.

THE USE OF FRUIT FRESH JUICES AS INHIBITORS OF ALUMINIUM ELECTROCHEMICAL CORROSION IN ALKALINE MEDIUM

In this article, the anticorrosion properties of inhibitors (that is, fruit and berry processing products) are studied using an electrochemical cell with irreversible electrodes as an example, in which cathode surface (aluminum sample for testing the class “AD1 pl”) is highly renewable. A sample of crudely processed copper (needed to minimize polarization at hydrogen evolution) of the “M00 k” class serves as an anode. A measure for corrosion is a change in the amperage of a galvanic electrochemical cell.

Polarization characteristics of four types of coating films by thermal spray in seawater solution

Thermal spray coating method has been known to be an attractive technique due to its relatively high coating speed. However, a high corrosion resistance of the coating film deposited by thermal spray method should be improved to prolong its lifetime. In this study, four types of coated films (DFT: 400 μm), that is, pure zinc, pure aluminum and two Al – Zn alloy ( Al : Zn = 85:15 and Al : Zn = 95:5) films were coated onto a carbon steel (SS401) with arc spraying, and the corrosion behaviors of these samples were investigated using the electrochemical method. The pure aluminum sample had the best corrosion resistance in seawater solution and alloy ( Al : Zn = 85:15) film, so called galvalume followed the pure aluminum sample, moreover, the alloy ( Al : Zn = 95:5) sample exhibited the worst corrosion resistance.

Manufacturing Process of Terahertz Radar Reflector Based on Ultra-Precision Machining Technology

This paper presents a technique for processing Terahertz radar reflector by SPDT (Single Point Diamond Turning) based on LODTM (Large Optics Diamond Turning Machine). This technique applies single crystal diamond cutting tools for ultra-precision machining, and thus could obtain high-precision optical mirror, which could be used as the Terahertz radar reflectors. An experiment for aluminum sample had been done to demonstrate the availability of the technique, and a pair of Terahertz radar reflectors were obtained. The precision of the reflectors, detected through precision coordinate measuring technology, was better than the designed requirement. The experiment results showed that Terahertz radar reflectors generated by deterministic ultra-precision machining technique based on LODTM would have advantages in figure accuracy and roughness and so on, which could be helpful to improve the precision and low the cost of Terahertz radar system.