Interface shear strength test and finite element analysis of SiC_f/TC17 composites

Abstract

The property of continuous SiC fiber reinforced titanium matrix composites is strongly affected by the interface strength.The interface shear strength of SiCf/TC17 was tested by fiber push-out test and then the microstructure of the sample was observed by SEM. The process of cooling from the composite consolidation temperature, specimen preparation for the push-out test, and the actual testing were simulated by using the finite element method. The initial temperature when residual stress begun to exist was identified through regarding the friction force when the fiber was completely separated from the matrix as the starting point.And the distribution of residual stress was analyzed before and after the sample preparation.The influence of the sample thickness and the fiber fraction volume on the distribution of the residual stress was studied.Cohesive zone model was used to analyze the interface chemical bonding strength.The results indicate that the initial temperature below which the residual stress starts to be generated is about 775 ℃.The residual shear stress is introduced at the interface after sample preparation.The difference between the test results of the interface shear strength and the interface chemical bonding strength is due to the existence of the interface residual shear stress.And the interface chemical bonding strength of SiCf/TC17 composites is about 450 MPa at room temperature.

Keywords

• titanium matrix composites
• interface strength
• residual stress
• cohesive zone model
• finite element analysis