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The purpose of this study is to investigate the cutting performance of amorphous carbon (a-C) coatings and hydrogenated amorphous carbon (a-C:H) coatings on machining 2A50 aluminum alloy. First-principles molecular dynamics simulation was applied to investigate the effect of hydrogen on the interaction between coatings and workpiece. The cross-section topography and internal structure of a-C and a-C:H films were characterized by field emission scanning electron microscopy and Raman spectroscopy. The surface roughness of the deposited films and processed workpiece were measured using a white light interferometer. The results show that the a-C-coated tool had the highest service life of 121 m and the best workpiece surface quality (Sq parameter of 0.23 &mu, m) while the workpiece surface roughness Sq parameter was 0.35 and 0.52 &mu, m when machined by the a-C:H-coated and the uncoated tool, respectively. Meanwhile, the build-up edge was observed on the a-C:H-coated tool and a layer of aluminum alloy was observed to have adhered to the surface of the uncoated tool at its stable stage. An interface model that examined the interactions between H-terminated diamond (111)/Al(111) surfaces revealed that H atoms would move laterally with the action of cutting heat (549 K) and increase the interaction between a-C:H and Al surfaces, therefore, Al was prone to adhere to the a-C:H-coated tool surface. The a-C coating shows better performance on cutting aluminum alloy than the a-C:H coating.

The effects of film thickness on the tribological behavior have been investigated for hydrogen-free diamond-like carbon coating in this paper. The film was deposited on cemented carbide substrate (YG10C) by applying a high power impulse magnetron sputtering (HiPIMS) technique. The reciprocating ball on the disc test was conducted on the film with different thicknesses from 0.66~1.26 &mu, m against the ZrO2 ball. The friction coefficient and wear resistance of the coating with different thickness showed a unimodal change. Numerous defects were observed on the surface of the film with a thickness of 0.66 &mu, m and the wear mechanism was mainly plow-grinding. Therefore, the steady-state friction coefficient reached the maximum value of 0.22. The coating with a thickness of 1.01 &mu, m had a higher sp3 content and a smoother, dense surface. A graphite transfer layer with low shear strength was detected on the ZrO2 ball against the film with a thickness of 1.01 &mu, m, which led to the reduction in friction, thus the steady-state friction coefficient reached the minimum value of 0.10. However, the internal stress of the film increased with increasing thickness due to the distortion of the bond angle of internal structure when the film was bombarded by high-energy particles. The peeling coating was observed under reciprocating sliding, which both played the role of plowing and boundary lubrication film. The steady-state friction coefficient was 0.14 with a coating thickness of 1.26 &mu, m. As a result, the hydrogen-free diamond-like carbon coating with optimized thickness shows a smooth and compact surface, low internal stress, high sp3 content, and better tribological properties.

The gradient composite TiAlSiN coatings were prepared by the cathodic arc ion technology. The tribological properties of TiAlSiN coating were investigated by the ball on disc tribological test in the humid atmosphere against various friction pairs. The results show that the TiAlSiN coating exhibited excellent mechanical properties. The corresponding wear mechanism varied with different friction pair under loads (2 N, 15 N, 25 N). The wear mechanisms of the coatings against stainless steel ball and ZrO2 ball were the adhesive wear and the abrasive wear, respectively. The wear rate and the friction coefficient of coating against Si3N4 ball were significantly decreased due to the generation of SiO2•nH2O layer. However, the SiO2•nH2O layer was weakened with the increasing of the load. Results show that the tribological properties of TiAlSiN coating are affected by the material of friction pairs. Lubrication film can be formed in a humid environment to improve the tribological properties of the coating.

This paper studies the five-axis NC machining simulation process for four-blade propeller. Three-dimensional solid model of four-blade propeller is created based on UG, and then the tool path is generated using its CAM module, and finally the machining simulation is implemented on FIDIA five-axis machining center based on VERICUT. The correctness of NC machining process is verified. The method of the virtual simulation is also suitable for similar parts machining.

Using the finite element method analysis the influence of the enhanced body size to stress concentration factor and stress distribution between the enhanced body in nanocomposite coating and the matrix interface. By preliminary calculation, the paper predicts a trend that the stress distribution on the interface reduces with the decreases of the enhanced body size and the stress concentration. Theoretically proved the iomportant rule that in the field of organic composite materials if you want to improve the performance of composite materials ,the enhanced body size need to be reduced.

Based on the research for the structure of the ceramic nanocomposites’ intragranular for Al2O3/ZrO2(n)，we did the test by the workpiece two-dimensional vibration grinding(WTDUVG), and focus on analyzing the characteristic and the effect element of the two-dimensional ultrasonic vibration grinding ceramic surface residual stress by the XRD diffraction. The result show that ceramic dimensional ultrasonic vibration grinding surface tensile stress is less than the same conventional grinding (CG) surface under tensile stress; two-dimensional ultrasonic vibration grinding surface residual compressive stress than conventional ground surface residual stress under the same grinding. Material removal mechanism of the grinding nature of the surface residual stress, when the material removaled by ductile deformation, grinding surface equal residual stress; when the material removaled by brittle- ductile mixed mode, the grinding surface tensile stress reduced, because the fracture of the ground surface, tensile stress released. As a results, the grit size of grinding wheel, Grinding depth and workpiece mechanical properties are the main technology factors affected the nature and size of the residual stress of ground surface.

After researching the mould coating and the effect of different matrix hardness on the service life, it can be concluded that under the condition, the matrix materials match with its obdurability well, the higher the matrix hardness, the longer the service life after the mould’s being coated. What’s more, it is put forward that when the heat treatment technology and the coating technology are worked out, the effect of the coating temperature on the matrix hardness should be turned over so as to avoid the matrix’s being annealing again and then have a further influence on the capability after being coated.

TiAlSiN coating was deposited on high-speed steel (HSS) samples and cemented carbide tool inserts, respectively, by a new coating preparation procedure, and its properties and cutting performance were characterized. The coating thickness, chemical composition, microstructure morphology and mechanical properties were investigated by X-ray fluorescence measurement system, energy dispersive spectrometer (EDS), scanning electron microscope (SEM), nanoindentation, Rockwell hardness tester and ball-on-disc tribometer. A 3D orthogonal cutting experiment model was established by DEFORM-3D to study the influences of different coating thicknesses on cutting force and temperature, and the field cutting experiment was carried out. The results show that the thickness of TiAlSiN coating is 3.14[Formula: see text][Formula: see text]m prepared by the 3[Formula: see text][Formula: see text]m preparation procedure, microhardness is 36.727[Formula: see text]GPa with the Si content of about 5.22[Formula: see text]at.% as well as good fracture toughness and adhesion strength. The TC4 and AISI 1045 cutting tool inserts with 4[Formula: see text][Formula: see text]m coating thickness have the minimum cutting forces of about 734.7[Formula: see text]N and 450.7[Formula: see text]N, respectively. Besides, tool inserts with a thickness of 3[Formula: see text][Formula: see text]m have the minimum cutting temperatures of about 510.2[Formula: see text]C and 230.6[Formula: see text]C, respectively.