The mechanical behavior dependence on the TiB whisker realignment during hot-working in titanium matrix composites

Weijie Lu,Deng Pan,Xiaohong Chen,Ke Zhang,Xinkuan Liu,Fengcang Ma,Ping Liu,Wei Li

doi:10.1038/srep36126

Abstract

Low-cost TiB whiskers reinforced titanium matrix composite (TMCs) was fabricated with enhanced mechanical performances using in situ technologies and hot working. Morphologies observation indicates that needle-like TiB whiskers with a hexagonal transverse section grow along the [010] direction due to B27 crystal structure and its growth mechanism. Mechanical properties tests show that the mechanical behavior of the TiB whiskers reinforced TMCs is dependent on the deformation amplitudes applied in hot-working. The improvement in yield strength by hot-working is attributed to the TiB whiskers realignment and the refinement of microstructure. Models are constructed to evaluate the realignment of TiB whisker during deformation and the increase in yield strength of the composite at elevated temperatures. These models clarify the alignment effect of TiB whiskers under various deformation amplitudes applied in hot-workings and reveals the yield strength dependence on TiB whiskers orientation.

Highlights

Low-cost TiB whiskers reinforced titanium matrix composite (TMCs) was fabricated with enhanced mechanical performances using in situ technologies and hot working
TiB ceramic is regarded as a powerful reinforcement because it presents excellent chemical stability and thermal stability in the Ti matrix[4,5,6,7,8]
transmission electron microscopy (TEM) bright field image of TiB and corresponding selected area diffraction patterns are presented in Fig. 1(b), which indicates that needle-like TiB whisker is B27 orthorhombic structure and lattice parameters a = 0.612 nm, b = 0.306 nm and c = 0.456 nm

Summary

Introduction

Low-cost TiB whiskers reinforced titanium matrix composite (TMCs) was fabricated with enhanced mechanical performances using in situ technologies and hot working. Mechanical properties tests show that the mechanical behavior of the TiB whiskers reinforced TMCs is dependent on the deformation amplitudes applied in hot-working. Models are constructed to evaluate the realignment of TiB whisker during deformation and the increase in yield strength of the composite at elevated temperatures. Numerous studies have been performed on hot-working to process TMCs based on the traditional hot-working technology of Ti alloys, such as rolling, extrusion and forging These studies indicate that mechanical properties of the composite are great dependent on the microstructure of matrix, inclusions and second phases, and these factors can be controlled by hot-working[27,28,29,30,31,32]. These studies may be very useful in the optimizing mechanical behavior of such composites

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Results