Enhanced High-Temperature Mechanical Properties of Al⁻Cu⁻Li Alloy through T1 Coarsening Inhibition and Ce-Containing Intermetallic Refinement.

Xinxiang Yu,Han Dai,Jie Sun,Dandan Shi,Xiaoyan Dong,Zhiguo Zhao

doi:10.3390/ma12091521

Abstract

The effects of the addition of 0.29 wt% Ce on the high-temperature mechanical properties of an Al–Cu–Li alloy were investigated. Ce addition contributes to T1 (Al2CuLi) phase coarsening inhibition and Ce-containing intermetallic refinement which greatly improved the thermal stability and high-temperature deformation uniformity of this alloy. On the one hand, small Ce in solid solution and segregation at phase interface can effectively prevent the diffusion and convergence of the main element Cu on T1 phase during thermal exposure. Therefore, the thermal stability of Ce-containing alloy substantiality improves during thermal exposure at the medium-high-temperature stage (170 °C to 270 °C). On the other hand, the increment of the tensile elongation in Ce-containing alloy is much greater than that in Ce-free alloy at high temperatures tensile test, because the refined Al8Cu4Ce intermetallic phase with high-temperature stability are mainly located in the fracture area with plastic fracture characteristics. This work provides a new method for enhancing high-temperature mechanical properties of Al–Cu–Li alloy which could be used as a construction material for high-temperature structural components.

Highlights

Al–Cu–Li alloy has a number of advantages over conventional aluminum alloy, such as lower density, higher strength, higher fracture toughness, better fatigue, and corrosion resistance [1,2]
The evaluation of thermal stability of Al–Cu–Li alloy is urgently needed for the potential application on fuselages, wing structures, bulkheads near the engine, as well as other high-temperature structural components which require high-temperature resistance in modern fighter aircraft [4]
Reports have been made on thermal exposure of Al–Cu–Li alloys at medium-high-temperatures [6,7]

Summary

Introduction

Al–Cu–Li alloy has a number of advantages over conventional aluminum alloy, such as lower density, higher strength, higher fracture toughness, better fatigue, and corrosion resistance [1,2]. These properties contribute to the improvement of payload and fuel efficiency, thereby having made Al–Cu–Li alloy a competitive alternative to conventional 2xxx and 7xxx series materials in new aircraft designs [3]. Materials near the engine, like bulkheads, are usually exposed to high-temperature environments (>200 ◦ C).

Objectives

Methods

Discussion

Conclusion