Aiming at the status of fewer researches on the anisotropy of single-crystal superalloy and micro-grinding temperature field, micro-grinding using the tool of < 1 mm in diameter to remove material is the final procedure of machining micro-parts. This paper firstly analyzes the anisotropy of surface-centered cubic structural material and establishes the theoretical model of elastic modulus and shearing modulus of single-crystal superalloy in the (001), (110) and (111) crystal plane. Afterward, it builds the three-dimensional simulation model of grinding temperature based on the Hill model, adopts any Lagrangian-Euler method to realize the simulation of micro-grinding temperature, gets the distribution of temperature field and changing situation during the micro-grinding through single-factor experiment and simulation analysis, and makes a study on the laws of different grinding depths, feeding rates, grinding velocities, different crystal planes {(001), (110) and (111)} and different crystal orientations in (001) crystal plane that affect the micro-grinding temperature, thus obtaining the crystal orientation which produces low grinding force and temperature. The result indicates that the grinding temperature increases with the increase in spindle speed, feeding rate and grinding depth; the grinding force and temperature are proportional to the elastic modulus and shearing modulus of the single-crystal material; the grinding temperature along (111) crystal plane is the highest, that of the (110) crystal plane is at the middle, and that along (001) is the lowest. When grinding in the (001) crystal plane, the normal grinding force and temperature along [110], [110] , [110] , [110] crystal orientations are the highest, and those along [100], [010], [100] , [010] crystal orientations are the lowest. And along with the aggravating of wear of abrasives on the grinding tool, the normal grinding force, tangential grinding force and grinding temperature all increase and the wear state of grinding tool can be judged online according to the signal of grinding force and temperature. These results provide an important evidence to do further research on the surface integrity of grinding single-crystal superalloy.

No abstract

No abstract

Metal substrates are widely used in engineering production. However, material life reduction and economic loss due to chemical and electrochemical corrosion are a major problem facing people. Electrochemical corrosion is the main corrosion mode of metals, such as seawater corrosion. It is found that the superhydrophobic surface treated by laser texturing plays an important role in the corrosion resistance of the substrate, with the laser texturing process and post-treatment affecting the corrosion resistance. The corrosion resistance is positively correlated with the superhydrophobic property of the surface. For the mechanism of corrosion resistance, this paper summarizes the effect of micro-nano structure, surface-modified coating, oxidation layer or new product layer, surface inhomogeneity, crystal structure, and slippery surface on corrosion resistance. Superhydrophobic surface and slippery surface are two common types of bioinspired, special wetting surfaces. In order to prepare better superhydrophobic and corrosion-resistant surfaces, this paper summarizes the selection and optimization of laser parameters, surface structure, processing media, and post-treatment from the point of view of mechanism and law. In addition, after summarizing the corrosion resistance mechanism, this paper introduces a series of characterization experiments that can measure the corrosion resistance, providing a reference for preparation and evaluation of the surface.

In the milling process, the coupling deflection and the dynamic characteristics of the cutter-workpiece system are time variant as the material removal and the change of cutter position. The milling stability of the system is dynamic because of the time-varying stiffness. In this study, the model of time-varying system has been developed. Variable pitch cutter (VPC) and variable spindle speed (VSS) are, respectively, typical method of passive control and active control to suppress the chatter, and two methods are compatible. The arithmetic of VPC and VSS combined method has been developed and verified effectively. Dynamic milling stability prediction of stiffness time-varying system for thin-walled components based on VPC and VSS combined method has been developed. And then, the dynamic milling stability of stiffness time-varying system for thin-walled components has been predicted. Keywords Thin-walled components • Dynamic milling stability • Stiffness time-varying system • VPC & VSS • SLD k Modal stiffness (N/mm) ξ Damping ratio ω n Natural frequency (Hz)