Abstract: The performance and wear mechanisms of one type of polycrystalline cubic boron nitride (PCBN) cutting tool with two different cutting edge micro geometries (marked as PCBN 169T and PCBN 169S) have been investigated in this paper. Interrupted turning of round GCr15 steel has been selected as the test method. The experimental results indicate that PCBN 169S has a greater thermal wear resistance than PCBN 169T at high cutting speeds. It is believed that edge preparation can shorten or eliminate the initiative wearing stage, improve the impact resistance, reduce the occurrence of chipping or dilapidation, and extend tool life. Scanning electron microscopy (SEM) were used to evaluate wear mechanisms of PCBN tools. Our results show that the dominant wear mechanisms for PCBN 169T and PCBN 169S are mechanical and chemical wear.
Abstract: This work present the study of the sintering of polycrystalline diamond compact with hyperbolic truncated cone profile using hexagonal boron nitride assembly, rather than salt mold, which is different from conventional assembly and this kind of polycrystalline diamond compact is widely used in percussion rock bits and roller cone rock bits. The well-sintered polycrystalline diamond compact without transition layer is prepared on a WC-10wt% Co substrate at temperature 1450°C for 3 min at non-hydrostatic high pressure of 5.5Gpa.Different analyzing techniques, such as X- ray diffraction, micro-Raman spectroscopy, scanning electron microscopy were applied to characterize the micro-structure, residual stress and sintering behavior. The SEM analysis indicates that diamond-diamond (D-D) direct bonding had formed in the polycrystalline diamond layer. The Raman spectroscopy shows compressive stress in the polycrystalline diamond layer is much higher than that sintered using traditional assembly.
Abstract: In this paper, Vibration-suspense-type process is used to develop a new material, metal or porcelain powder coated with resin or ceramic powder, then it can be sintered and formed without large-power laser. One set of vibration-suspense-type powder-coating equipment is developed and powder material suitable for SLS can be prepared with the equipment. The moving status and the moving process of powder granule in the vibration-suspense-type process are also analyzed. Based on the equipment, Polystyrene-Al powder material, which is suitable for SLS, is successfully prepared. And the optimum process is discussed.
Abstract: The ratio of TC4 titanium alloy’s yield strength (σs) and elastic modulus is very high . Springback amount of TC4 forming is big at room temperature and the quality of TC4 part can be inferior . TC4 titanium alloy needs to be amended after it is formed .The article does the hot sizing experiment study of TC4 titanium alloy. The influence laws of some factors are gotten, which include the process parameters of induction heating and so on. The article establishes the model of TC4’s hot sizing through ANSYS software. Hot sizing numerical simulation of TC4 is done through ANSYS LS-DYNA solution. Some rules and optimum parameters are found., which are expected to be applied to the production. Keywords:TC4 titanium alloy (Ti-6Al-4V); hot sizing; high frequency induction; experiment research
Abstract: Laser cladding technology is used to prepare TC11 titanium alloy surface coated CBN. Through the finite element method to simulate the movement of scratch experiment. When coating is under normal force and tangential force, through changing the thickness of the layers , the coating crack length and width of crack, coating in force is analyzed when the interface stress affects on coating.Simulations that the interface stress value of 0.2mm coating reach to 1.485Gpa, The interface stress value of 0.5mm crack length reach to 0.3707Gpa, The interface stress value of 0.06mm crack width reach to 0.2234Gpa.
Abstract: In transversely isotropic piezoelectric bi-materials, a theoretical analysis is followed to calculate the dynamic stress intensity factors (DSIFs) due to existence of a permeable interfacial crack, near the edge of a circular cavity. The model is subjected to dynamic incident anti-plane shearing (SH-wave) and Green's function method is the base of formulation. Conjunction and crack-simulation techniques are applied to obtain DSIFs at the crack’s inner tip. Calculations are prepared based on FORTRAN language program. For calibration of program, a comparison is accomplished between the present model and another with a crack emerging from the cavity edge. Calculating results clarified the influences of the physical parameters, the structural geometry and the wave frequencies on the dimensionless DSIFs and how those affected the efficiency of piezoelectric devices and materials.
Abstract: Based on the theory of target curve, a method of improving flatness target curve is proposed. The transverse temperature distributions of strip are measured and described with a biquadratic expression, and the statistics method is used to analyze the temperature distributions. Finally, the additional temperature stress compensation is calculated to improve the strip shape.
Abstract: Corrosion inhibitor-inorganic clay composite including 2-mercaptobenzimidazole (MBI) anions intercalating Zn-Al layered double hydroxides (LDHs) assembled via anion-exchange reaction. Powder X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectrum analysing and scanning electron microscopy (SEM) indicate that the MBI anion are successfully intercalated into the LDHs interlayer. The benzene plane is horizontal arrangement rather than vertical orientation in the interlayer spacing. The active anticorrosive property of AA2024 alloy with the active anticorrosion coating is evaluated by electrochemical impedance spectroscopy (EIS). The sol-gel coating doped with the LDHs clearly demonstrates long-term anticorrosive performances compared to the undoped sol-gel coating, due to the release of corrosion inhibitor from the LDHs.
Abstract: Nickel-based super alloy, niobium alloy, refractory metal and carbon fiber reinforced composite are the most common structural materials used in aviation and spaceflight fields. Reduced oxidation and corrosion resistance at high temperature are limiting factors to the application of theses materials. Adapted protective coatings such as pure precious metal coatings, precious metal alloy and precious metal composite coatings can be applied on the surface of theses materials. New advances of oxidation protective coating in recent years are reviewed in this paper, combined with some research on the preparation of iridium