MILLING EFFECTIVENESS INCREASE BY MEANS OF HARD-ALLOY COMPOUND END MILLING CUTTERS

The investigation purpose: the effectiveness increase of hard-alloy end milling cutters at the expense of new milling cutter design development conventionally called compound milling cutters. The problem solved during investigation: the reveal of the most efficient fields of compound milling cutter use. The scientific novelty of the work: the formation of a new kind of hard-alloy end milling cutter design, to avoid milling cutter destruction in the place of shank end mounting in the chuck of the machine a shank end is made of structural steel and soldered with a hard-alloy cutting part of the milling cutter. As a result of the investigation it was defined: a) compound milling cutters compete with monolithic milling cutters in accuracy during billet production of parts at a lower cost of milling cutters; b) a compound milling cutter with a diameter of 16 mm and a milling cutter length of 92 mm substitute successfully a monolithic milling cutter by production accuracy and ensures cost reduction of a product by 4%; c) a compound milling cutter with a length of 220 mm as compared with a monolithic milling cutter ensures product cost reduction by 38% and applicable for general aims at engineering enterprises.

Microscopic Characteristics and Properties of Fe-Based Amorphous Alloy Compound Reinforced WC-Co-Based Coating via Plasma Spray Welding

Plasma spray welding, as one of the material surface strengthening techniques, has the advantages of low alloy material consumption, high mechanical properties and good coating compactness. Here, the Co alloy, WC and Fe-based amorphous alloy composite coating is prepared by the plasma spray welding method, and the coating characteristics are investigated. The results indicate that the coatings have a full metallurgical bond in the coating/substrate interface, and the powder composition influences the microstructures and properties of the coating. The hardness of coatings increases with the mass fraction of the Fe-based amorphous alloy. The spray welding layer has a much higher wear resistance compared with the carbon steel, and the Fe-20 exhibits a superior wear resistance when compared to others. The results indicate that the amorphous alloy powders are an effective additive to prepare the coating by plasma spray welding for improving the wear resistance of the coating.

Mechanical Behavior of AA2124 Alloy with 12 wt. % of B4C Particulates Reinforced Composites

In the current investigation, the mechanical properties of AA2124-12 wt. % of B4C composites were displayed. The composites containing 12 wt. % of B4C in AA2124 alloy were synthesized by liquid metallurgy method. For the composites, fortification particles were preheated to a temperature of 400˚C and afterward added in ventures of two into the vortex of liquid AA2124 alloy compound to improve the wettability and dispersion. Microstructural examination was carried out by SEM. Mechanical properties of as cast AA2124 alloy and AA2124-12 wt. % of B4C composites were evaluated as per ASTM standards. Microstructural characterization by SEM confirmed the distribution and presence of micro boron carbide particles in the AA2124 alloy matrix. The hardness, ultimate strength, yield strength and bending behaviour of AA2124 alloy enhanced with the incorporation of 12 wt. % of micro B4C particles. Further, ductility of AA2124 alloy decreased with the presence of B4C particles. Tensile fractography were studied on the tested samples to know the various fractured mechanisms

Tribological Behavior of Nanolubricants Based on Coated Magnetic Nanoparticles and Trimethylolpropane Trioleate Base Oil

The main task of this work is to study the tribological performance of nanolubricants formed by trimethylolpropane trioleate (TMPTO) base oil with magnetic nanoparticles coated with oleic acid: Fe3O4 of two sizes 6.3 nm and 10 nm, and Nd alloy compound of 19 nm. Coated nanoparticles (NPs) were synthesized via chemical co-precipitation or thermal decomposition by adsorption with oleic acid in the same step. Three nanodispersions of TMPTO of 0.015 wt% of each NP were prepared, which were stable for at least 11 months. Two different types of tribological tests were carried out: pure sliding conditions and rolling conditions (5% slide to roll ratio). With the aim of analyzing the wear by means of the wear scar diameter (WSD), the wear track depth and the volume of the wear track produced after the first type of the tribological tests, a 3D optical profiler was used. The best tribological performance was found for the Nd alloy compound nanodispersion, with reductions of 29% and 67% in friction and WSD, respectively, in comparison with TMPTO. On the other hand, rolling conditions tests were utilized to study friction and film thickness of nanolubricants, determining that Fe3O4 (6.3 nm) nanolubricant reduces friction in comparison to TMPTO.

Effect of Deep Cryogenic Treatment on Microstructure and Wear Resistance of LC3530 Fe-Based Laser Cladding Coating

The effect of deep cryogenic treatment on microstructure and wear resistance of LC3530 Fe-based powder laser cladding coating was investigated in this paper. The cladding coating was subjected to deep cryogenic treatment for the different holding times of 3, 6, 9, 12, and 24 h, followed by tempering at room temperature. Microstructure of the cladding coating was observed by optical microscope (OM) and the microhardness was measured by the Vickers-hardness tester. The wear was tested by ball and flat surface grinding testing conducted on the material surface comprehensive performance tester. The wear scars were analyzed using a non-contact optical surface profiler and scanning electron microscope (SEM). The results showed the grain size of cladding coating after 12 h of deep cryogenic treatment was significantly reduced by 36.50% compared to the non-cryogenically treated cladding coating, and the microhardness value increased by approximately 34%. According to the wear coefficient calculated by the Archard model, the wear resistance improved about five times and the wear mechanism was micro-ploughing. The deep cryogenic treatment could enhance the wear resistance of the cladding coating by forming a wear resistant alloy compound and higher surface microhardness.

Laser-Ignited Self-Propagating Sintering of AlCrFeNiSi High-Entropy Alloys: An Improved Technique for Preparing High-Entropy Alloys

AlCrFeNiSi system porous high-entropy alloy material is manufactured by laser ignition and self-propagating sintering of natural chromite powder, which provides the idea of breaking the traditional synthesis procedure of high-entropy alloy compound material. The raw material powder obtained by ball milling is compacted into cylindrical compacts, and the self-propagating reaction comes from the ignition caused by the laser on the surface of compacts, the high-entropy alloy composite of chrome iron powder synthesized by laser sintering, is obtained as well. The raw material is prepared from Al, Cr, Fe, Ni and Si elements with similar effective components of natural chromite powder. The selected chromite powder is energy-saving and environment-friendly, so the preparation of high-entropy alloy by the low-cost short-process can be made for processing for pre-theoretical reserve and process design. The effect of Si content on microstructure and properties of AlCrFeNiSi high-entropy alloy is investigated.

Analysis on Development Status and Trend of Vehicle Materials Your

Vehicle engineering materials are used in manufacturing of vehicle. Its status quo and development trend are analyzed. Proportion of steel in structure material will reduce stage by stage. With reliable performance, steel will be replaced by light and new-style materials such as aluminous alloy, compound materials. Plentiful developing rapidly new materials, such as macromolecule materials, compound materials, offer necessary condition to develop vehicle.

Reliability Laboratory Analysis of PCB Surface Coating Based on ENEPIG

Electroless palladium are introduced to ENEPIG surface coating technology, from reaction principle to prevent oxidation of nickel-plated, but the process conditions and parameters of practical application are whether or not mass-produce condition , need using a series of reliability experiments to validate it , to reduce risk coefficient of mass-produce , to satisfy customer requirement. Therefore, put forward a package of experimental programs, including experiment projects, experiment methods, instrument and equipment for test, evaluate requirement, test result and analysis etc , especially using TEM have in-depth analysis for interface alloy compound of ENEPIG coating player with SAC305 , systematically verified ENEPIG production technology are mature and reliable, it is considered to be versatile surface coating technology, and particularly suitable for application in gold bonding and surface mount hybrid assembly board which are high connecting reliability product, completely replace the current ENIG technology.

Synthesis and Characterization of Ultrafine Nanocrystalline Ti-Al Nanoparticles

Ti-Al nanoparticles and have been synthesized by the flow-levitation (FL) method. The morphology, crystal structure and chemical composition of Ti-Al nanoparticles obtained were investigated by transmission electron microscopy, X-ray diffraction and induction-coupled plasma spectroscopy. Results showed that the average grain size of these nanoparticles is about 30 nm, and it can be controlled availably by altering procedure parameters. The structure of powder is mainly double phase Ti-Al particulate composite. In addition, there are certain corresponding relation between the compositions of evaporate source master material and phase composition of alloy compound nanoparticle. The expected nanoparticle, which is mainly composition of nanocrystalline intermetallic compound, can be obtained through changing the compositions of evaporating source mastermaterial.