In order to implement cost-effective machining of gr anite materials with diamond impregnated tools, we should realize low tool w ear, low energy consumption, and high cutting efficiency, while the accuracy of the wor...In order to implement cost-effective machining of gr anite materials with diamond impregnated tools, we should realize low tool w ear, low energy consumption, and high cutting efficiency, while the accuracy of the workpiece surfaces are maintained to be satisfactory. It is understood that the main factors affecting the tool wear, the energy, and the efficiency during the machining process are related to the tribological interactions that occur at the interface between the diamond tool surface and the workpiece. Based on this consideration, we propose a new machining method to machine granite materia ls to achieve improved cost effectiveness. In the proposed method, the tribologi cal interactions are maintained to a minimum. Based on the analyses of the experimental results, the following conclusions can be drawn: The wear performance is greatly dependent on the machining parameters and their combination. Therefore, optimum machining parameters must be set up at first in order to optimize the tribological characteristics of segments and thereby sawbl ade performance. These may be realized by balancing the energy expended by frict ion and the mechanical load on diamond crystal. The geometry and structure of diamond segments are another important criterion f or the diamond saw blade. Using a seven-layer structure for multi-blades sawin g and applying segments with side slots for trimming application had greatly red uced the frictions in the sawing processes. The wetting and bonding between diamonds and matrix alloys have been considered as the prerequisite for high wear performance of the segments. Diamonds coated w ith Ti-Cr alloy by a unique technique can effectively improve its wetting c apability and provide more storage space for debris, thereby reducing friction i nteractions.展开更多
Nanocomposites based on ethylene vinyl acetate (EVA) and montmorillonite (MMT) were prepared using melt mixing of the two components and an intercalation agent hexadecyl trimethyl ammonium bromide(CTAB).The struc ture...Nanocomposites based on ethylene vinyl acetate (EVA) and montmorillonite (MMT) were prepared using melt mixing of the two components and an intercalation agent hexadecyl trimethyl ammonium bromide(CTAB).The struc ture and properties of EVA/clay nanoco mposites were characterized by XRD,TGA,Molau and mechanical properties tests.The results showed that EVA could be intercalated into the galleries of layered sil icates in these samples,and the distance between layers of MMT in the EVA matrix was 4.09 nm.Interface adhesion between the components in the EVA/MMT (95/5) nan ocomposites was improved because the contact area between MMT layers and EVA mat rix increased and there was a great deal of active sites on the surface of MMT l ayers,which could bind tightly with the EVA matrix.Compared with those of EVA/MM T (95/5) composites without CTAB,the tensile strength,the Young’modulus and the tear strength of EVA/MMT (95/5) nanocomposites prepared in this work increased b y about 20 2%,43 3% and 17 1%,respectively.The thermal behavior of the compos ites was examined on a thermobalance in nitrogen.For the EVA/MMT (95/5) nanocomp osites,the acceleration of EVA deacylation and the deceleration of thermal degra dation were observed.展开更多
文摘In order to implement cost-effective machining of gr anite materials with diamond impregnated tools, we should realize low tool w ear, low energy consumption, and high cutting efficiency, while the accuracy of the workpiece surfaces are maintained to be satisfactory. It is understood that the main factors affecting the tool wear, the energy, and the efficiency during the machining process are related to the tribological interactions that occur at the interface between the diamond tool surface and the workpiece. Based on this consideration, we propose a new machining method to machine granite materia ls to achieve improved cost effectiveness. In the proposed method, the tribologi cal interactions are maintained to a minimum. Based on the analyses of the experimental results, the following conclusions can be drawn: The wear performance is greatly dependent on the machining parameters and their combination. Therefore, optimum machining parameters must be set up at first in order to optimize the tribological characteristics of segments and thereby sawbl ade performance. These may be realized by balancing the energy expended by frict ion and the mechanical load on diamond crystal. The geometry and structure of diamond segments are another important criterion f or the diamond saw blade. Using a seven-layer structure for multi-blades sawin g and applying segments with side slots for trimming application had greatly red uced the frictions in the sawing processes. The wetting and bonding between diamonds and matrix alloys have been considered as the prerequisite for high wear performance of the segments. Diamonds coated w ith Ti-Cr alloy by a unique technique can effectively improve its wetting c apability and provide more storage space for debris, thereby reducing friction i nteractions.
文摘Nanocomposites based on ethylene vinyl acetate (EVA) and montmorillonite (MMT) were prepared using melt mixing of the two components and an intercalation agent hexadecyl trimethyl ammonium bromide(CTAB).The struc ture and properties of EVA/clay nanoco mposites were characterized by XRD,TGA,Molau and mechanical properties tests.The results showed that EVA could be intercalated into the galleries of layered sil icates in these samples,and the distance between layers of MMT in the EVA matrix was 4.09 nm.Interface adhesion between the components in the EVA/MMT (95/5) nan ocomposites was improved because the contact area between MMT layers and EVA mat rix increased and there was a great deal of active sites on the surface of MMT l ayers,which could bind tightly with the EVA matrix.Compared with those of EVA/MM T (95/5) composites without CTAB,the tensile strength,the Young’modulus and the tear strength of EVA/MMT (95/5) nanocomposites prepared in this work increased b y about 20 2%,43 3% and 17 1%,respectively.The thermal behavior of the compos ites was examined on a thermobalance in nitrogen.For the EVA/MMT (95/5) nanocomp osites,the acceleration of EVA deacylation and the deceleration of thermal degra dation were observed.
