Microstructural Modeling and Strengthening Mechanism of TiB/Ti-6Al-4V Discontinuously-Reinforced Titanium Matrix Composite

Abstract

A novel modeling method was proposed to provide an improved representation of the actual microstructure of TiB/Ti-6Al-4V discontinuously-reinforced titanium matrix composite (DRTMC). Based on the Thiessen polygon structure, the representative volume element (RVE) containing the complex microstructures of the DRTMC was first generated. Thereafter, by using multiple user-defined subroutines in the commercial finite element software ABAQUS, the application of asymmetric mesh periodic boundary conditions on the RVE was realized, and the equivalent elastic modulus of the DRTMC was determined according to the homogenization method. Through error analyses on the experimental and calculated results regarding the equivalent elastic parameters of the DRTMC, the rationality of generating the DRTMC finite element model by using the present method was validated. Finally, simulations based on four types of network-like models revealed that the present simplifications to the particle shape of the reinforcement phase had less of an influence on the overall composite strength. Moreover, the present study demonstrates that the DRTMC enhancement is mainly attributed to the matrix strengthening, rather than the load-transferring mechanism. The strengthening influences of the distribution forms of the reinforcement phases, including their distribution density and orientation, were studied further. It was found that both the higher distribution density and limited distribution orientation of the particles would increase the probability of overlapping and merging between particles, and; therefore, higher strength could be yielded when the volume fraction of the reinforcement phase reached a certain threshold. Owing to the versatility of the developed methods and programs, this work can provide a useful reference for the characterization of the mechanical properties of other composites types.

Influence of Layer-Thickness Proportions and Their Strength and Elastic Properties on Stress Redistribution during Three-Point Bending of TiB/Ti-Based Two-Layer Ceramics Composites

“…The main influences on the properties of composites are the methods of their production and the proportion and structure of borides in the volume of the material. Titanium composite materials with TiB 2 - [6][7][8][9][10] and TiB [11][12][13][14][15][16][17][18]-strengthening phases have been extensively studied. The structure of titanium borides is strongly influenced by high degrees of material deformation, which lead to significant grain refinement and texture formation [18,19].…”

Enhanced stress concentration sensitivity of SiCp/Al composite with network architecture

“…25 This implies that a large enough model size is required. 16 Two-dimensional (2D) honeycomb structure 26 and Voronoi cells (Thiessen polygons) 27 have been used for TiBw/Ti network composites. However, these models were over simplified and cannot represent 3D network architecture.…”