Investigations on the mechanics and tribology of multilayer graphene nanosheet in TiAl aviation composites

Zhao Dong,Feizhi Zhang,Kang Yang

doi:10.1177/16878140211040714

Abstract

Requirements of low energy consumption and material-volume reduction in the aerospace industry have spurred improvements of mechanical and tribological behaviors of TiAl (TA) alloys. TA-graphene (TAG) has poorer mechanical properties (6.02 ± 0.42 GPa nano-hardness, 150 ± 12.32 GPa elasticity modulus, and 802 ± 21 MPa yield strength) than (6.25 ± 0.52 GPa nano-hardness, 159 ± 14.21 GPa elasticity modulus, and 850 ± 19 MPa yield strength) of TA-graphene-silver (TAGS). Multilayer graphene nanosheets were curled into small loops to resist the applied forces, and helped to improve the mechanical properties of the TAGS. Subsequently, the graphene nanosheets enhanced the tribological performances as observed by the ball-on-disk tribometer. The following factors were primarily responsible for more excellent tribological behaviors (approximately 0.27 friction coefficient, 2.82 × 10−4 mm3 N−1 m−1 wear rate) of TAGS than those of the TAG: intra-lamellar separation of graphene, graphene-enhanced capacity of wear scar, plastic deformation of silver, the excellent cooperation lubrication of graphene-silver, the low-hardness lubrication film on the grain-refined layer, the well-distributed film grain, and low grain orientation angles.

Highlights

In recent years, TiAl (TA) alloys have been extensively used for the manufacture of lightweight components in the aerospace industries, such as the turbine blades and turbochargers.[1,2,3] But, the poor tribological and mechanical properties of TA-based components have impeded their applicabilities,[4,5] especially under extreme conditions
This paper investigated the enhancements of mechanical and tribological properties of multilayer graphene nanosheets in TA composites
The following conclusions were drawn: (1) For a TAG, graphene nanosheets that were parallel to the applied tension caused interlamination separation in the multilayered nanosheets, while the graphene sheets perpendicular to the applied tension effectively hindered stresses and produced a high strength of approximately 802 modulus (GPa) Yield strength (MPa)

Summary

Introduction

TiAl (TA) alloys have been extensively used for the manufacture of lightweight components in the aerospace industries, such as the turbine blades and turbochargers.[1,2,3] But, the poor tribological and mechanical properties of TA-based components have impeded their applicabilities,[4,5] especially under extreme conditions. To improve the friction and wear behaviors of these components, most researchers have focused on preparing self-lubricating samples containing silver.[6,7,8] Xu et al.[6] studied the effect of the migration of silver atoms on the tribological behaviors of materials. To the best of our knowledge, few works have reported on the improvements of mechanical and tribological performances of TA-based composites by the graphene enhancement or the effect of spherical graphene-silver on the tribological behaviors of TA composites.

Results

Conclusion