Research On Characterization And Evaluation Of Dimensional Stability For C_f/Mg Composites Plate

The dimensional stability of new materials and its components is the most important property which determine whether its can applicate in the field of precision machinery manufacturing or not.It directly affects the dimensional accuracy and mechanical properties in its manufacturing,storing,assembling and other processes.Carbon fiber reinforced magnesium based composites(C_f/Mg)plate fabricated by Liquid-solid extrusion following vacuum infiltration technique(LSEVI)as a componments has a specific strength and stiffness ratio,excellent machining performance.However,the research on Characterization and Evaluation of Dimensional stability for C_f/Mg Composites Plate is not sufficient.Carbon fiber reinforced magnesium based composites(C_f/Mg)have many advantages like high specific strength,high specific modulus,good dimensional stability and good machinability.C_f/Mg composite has favorable application foreground as structural or functional material.Liquid-solid extrusion following vacuum infiltration technique(LSEVI)is a novel fabricating process for magnesium based composites.Composites fabricated by LSEVI has superior mechanical properties,however,the characterization and evaluation of dimensional stability and regular elastic deformation were under-researched.In this paper,the C_f/Mg composites fabricated by LSEVI was the main subject.The method for the characterization of dimensional stability was proposed.A testing program was designed for the elasticity modulus and micro-yield strength of continuous fiber reinforced metal matrix composites.Surface physical properties and practical problems in the experiments were analyzed.Based on the electronic universal testing machine,the experimental program for tensile strain using strain gauges combining with the strain measurement method in the electrometrical method.The method for the preparation process of specimens was summarized.Tensile experiments using specimens made of AZ91 D and ZL102 alloy were conducted in order to validate the experimental program.The result showed the experimental system was stable and reliable.79 sets of specimens made of C_f/Mg composites by LSEVI were prepared and tested using the tensile experimental program.The experimental limit value of the elasticity modulus was obtained by interpolation and curve fitting.Then the trustworthy range of elasticity modulus was determined by theoretical calculation and Weibull distribution.Finally,three tensile failure modes which resulted in the tensile failure of C_f/Mg composites were summarized and analyzed.Different methods for the micro-yield strength experiments were analyzed.The experimental program of micro-yield strength,the preparation of specimens and the experimental procedure for C_f/Mg composites were determined to characterize the ability of micro-plastic deformation resistance.After analysis and comparison of the experiment results,the micro-plastic deformation resistance ability of C_f/Mg was studied.The results laid the foundation of characterization and evaluation of dimension stability under short-term load.The long-term observation scheme and device along the vertical direction was designed for the C_f/Mg composite annular plate parts.Experimental data of the long-term observation for the dimension deformation were recorded for almost a year.The reason of the dimension deformation were analyzed combined with an analysis of the literature.Experimental methods for regular tensile mechanical properties and micro-yield strength of continuous fiber reinforced metal matrix composites were proposed in this study.The tensile modulus and micro-yield strength of C_f/Mg composites fabricated by LSEVI were characterized and evaluated.The dimension deformation process of the annular plate parts were early studied.This research laid the foundation for the further application of C_f/Mg composites used in precision machinery manufacturing,aerospace Instrumentation and other fields.