Study On The Mechanism Of Molybdenum Fiber Reinforced Resin Mineral Composite

It is one of the effective means to improve the comprehensive property of the machine tools by researching and developing new-style machine tool elementary materials with superior performance. The resin mineral composite, also known as the artificial stone, is famous for good damping properties, which is about ten times stronger more than ordinary gray cast iron, meeting the high-speed, precision and high thermal stability requirements on machine tools, it can be applied to manufacturing the elementary parts of high-speed and high precision processing machine tools. Aiming at the poor mechanical properties of resin mineral composites, the thesis uses high strength molybdenum fibers to improve its mechanical properties.Old molybdenum fibers are molybdenum wires scraped by Wire Cut Electric Discharge Machining (WEDM), on the surface of which vast discharged pits are distributed randomly. The physical model of resin mineral composite reinforced by molybdenum fibers is established to analyze interface mechanism, and then to obtain the interface combination between the molybdenum fibers and resin matrix. The interface combination between old molybdenum fibers and resin matrix is achieved by the mechanical lock junction, liquid infiltration on the surface of the solid and the mutual diffusion between atoms or molecules; the surface of new molybdenum fibers is smooth and the phenomenon of mechanical lock can be ignored, so its interface combination is mainly achieved through liquid infiltration on the surface of the solid or the mutual diffusion between atoms or molecules. The results of tensile properties tests on the old and new molybdenum fibers show that:the plastic deformation stage of old molybdenum fibers is very short and plastic strain hardly occurs, therefore, they are more suitable for enhancing the resin mineral composite.Finite element models are established to analyze the interfacial bond strength and interfacial slip resistance between the molybdenum fibers and the resin matrix. The results show that old molybdenum fibers surpass new molybdenum fibers in the ability of limiting the composite deformation and bearing the load. When the interfacial slip resistance is less than the maximum tensile strength of molybdenum fibers, the maximum load withstood by the molybdenum fibers reinforced resin mineral composite is in direct proportion with the number of discharge pits. Compared with new molybdenum fibers, the interfacial slip resistance between old molybdenum fibers and resin matrix is stronger and the old molybdenum fibers withstand more load at the debonding surface, so the old molybdenum fibers is better for enhancement.Tests on the bending strength and compression strength of resin mineral composite reinforced by old and new molybdenum fibers are carried out. The results show that the old and new molybdenum fibers can both play an enhanced effect, compared with the latter one, the former effect is better and the cost is lower. The compression strength of resin mineral composite reinforced by new molybdenum fibers is increased by4.9%, the bending strength by22.6%; and the compression strength of resin mineral composite reinforced by old molybdenum fibers is increased by12.7%, the bending strength by32.5%.A research has been done on the enhancement mechanism of resin mineral composite with straight molybdenum fibers and profiled molybdenum fibers; a profiled molybdenum fiber pullout model is built and an expression of maximum drawing force of four kinds of profiled molybdenum fibers is found. Under the condition of the same bending deformation angle and the little influence of stress concentration, the maximum drawing force of four kinds of profiled molybdenum fibers in order of size is W-shape>U-shape>N-shape>V-shape. Tests on bending strength and compression strength of the resin mineral composite reinforced by four kinds of profiled molybdenum fibers are also carried out and the results show that the enhanced effect of profiled molybdenum fibers on the mechanical properties of resin mineral composite is better than that of straight molybdenum fibers, with the W-shape molybdenum fibers most effective, which is almost consistent with the theoretical analysis results.