The goal of this study is to analyze the material deformation behavior in the micron level by quasi-static and dynamic impact tests of hat shaped specimen. Three type of specimen with different shear ring thicknesses (800μm, 400μm, 50μm) were designed. The quasi-static and dynamic impact tests were performed by electronic universal testing machine and split Hopkinson pressure bar (SHPB) respectively. During the material deformation in the SHPB test, the value scope of strain is 0 to 9 while the value scope of strain rate is 0.001s-1 to 400000s-1. The size effect phenomenon on shear stress and failure strain with different shear ring thickness was investigated. The shear stress and failure strain of material increases with the decrease of shear ring thickness. And the size effect phenomenon was weakened with the increase of strain rate.

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In the present research work, a new precision sawing technique is proposed, by which the ceramic workpiece is ultrasonically vibrated along the blade radial direction during the sawing operation using a diamond blade. In this study, experiments are conducted to study the sawing force characters of ultrasonic vibration-assisted sawing (UVAS) and conventional sawing (CS). The influences of the sawing parameters on the sawing force and force ratio are investigated. The results show that the sawing force in UVAS is smaller than those in CS. It was found that applying ultrasonic vibration to the sawing operation decreased the normal sawing force 18%-38% and tangential sawing force by 10%-25%. The force ratio in UVAS is lower than that in CS, which reveals that diamonds are easier to cut into the ceramic workpiece and the material machinability is improved.

Grinding process can be considered as micro-cutting processes with a lot of irregular abrasive grits on the surface of grinding wheel. The study of the grit-workpiece interaction through single grit cutting is an important contribution to describe the material removal processes in the grinding process. In this study, single grit cutting processes with different process parameters (depth of cut, cutting speed) were modeled by FEM software AdvantEdge. The critical depth of cut from plowing t cutting was investigated. The simulated tangential and radial cutting forces increase sharply due to the pile-up of workpiece material in the front of single grit when the depth of cut reached to some value. And the increase extent of cutting forces at low cutting speed is larger than that at high cutting speed due to the thermal softening of workpiece material. The simulated highest cutting temperature increase first, and then decrease, finally increase again with the increase of depth of cut. And the peak value of simulated highest cutting temperature occurs near the critical depth of cut. The simulated material removal rate increases with the increase of cutting speed and depth of cut.

In this study, a number of experiments on surface grinding of nanostructured WC/12Co (n-WC/12Co) coatings were conducted on a precision surface grinding machine with a horizontal axis and rectangular worktable. The residual stresses in the as-sprayed and ground n-WC/12Co coatings were measured with the X-ray diffraction method. According to the experimental study and theoretical analysis, this paper investigates the influences of grinding parameters, such as depth of cut, feedrate of workpiece, abrasive grit size and wheel bond type on residual stresses precision grinding of n-WC/12Co coatings.