A review on forming techniques for manufacturing lightweight complex—shaped aluminium panel components

In recent years, a great effort has been devoted to developing a new generation of materials for aeronautic applications. The driving force behind this effort is the reduction of costs, by extending the service life of aircraft parts (structural and engine components) and increasing fuel efficiency, load capacity and flight range. The present paper examines the most important classes of metallic materials including Al alloys, Ti alloys, Mg alloys, steels, Ni superalloys and metal matrix composites (MMC), with the scope to provide an overview of recent advancements and to highlight current problems and perspectives related to metals for aeronautics.

Alloys for aeronautic applications: State of the art and perspectives

Thermal stability, determining the material ability of retaining its properties at required temperatures over extended service time, is becoming the next frontier for aluminum alloys. Its improvement would substantially expand their range of structural applications, especially in automotive and aerospace industries. This report explains the fundamentals of thermal stability; definitions, the properties involved; and the deterioration indicators during thermal/thermomechanical exposures, including an impact of accidental fire, and testing techniques. For individual classes of alloys, efforts aimed at identifying factors stabilizing their microstructure at service temperatures are described. Particular attention is paid to attempts of increasing the current upper service limit of high-temperature grades. In addition to alloying aluminum with a variety of elements to create the thermally stable microstructure, in particular, transition and rare-earth metals, parallel efforts are explored through applying novel routes of alloy processing, such as rapid solidification, powder metallurgy and additive manufacturing, engineering alloys in a liquid state prior to casting, and post-casting treatments. The goal is to overcome the present barriers and to develop novel aluminum alloys with superior properties that are stable across the temperature and time space, required by modern designs.

Thermal Stability of Aluminum Alloys.

Pre-strain-dependent natural ageing and its effect on subsequent artificial ageing of an Al-Cu-Li alloy

Coarsening kinetics and strengthening mechanisms of core-shell nanoscale precipitates in Al-Li-Yb-Er-Sc-Zr alloy

Strengthening mechanisms, deformation behavior, and anisotropic mechanical properties of Al-Li alloys: A review

This study was carried out to investigate the effect of preliminary processes on tube hydroforming (THF) and to optimize the THF process parameters to achieve a sound complex 3D curved intercooler pipe without failure by numerical and experimental approaches. The effect of three-step rotary bending on the thickness distribution and microstructure of the tube has been evaluated. The necessity of heat treatment is analyzed prior to the THF process. The stroke of punches should be optimized separately according to the asymmetry geometry characteristics of the intercooler pipe. The suitable loading path is discussed during the THF process. The results obtained from simulation keep a reasonable agreement with that from the experiment.

The effect of tube bending, heat treatment and loading paths on process responses of hydroforming for automobile intercooler pipe: numerical and experimental investigations

Prediction of tensile deformation behavior of Al-Li alloy 2060-T8 by computational homogenization-based crystal plasticity finite element method

Effect of novel impact hydroforming technology on the formability of Al alloys

Springback is a tough issue in sheet forming, and always leads to dimensional inaccuracy of formed parts. Titanium alloy selected as desired light-weight alloy has been playing significant roles in aerospace industry because of its good comprehensive performance. Whereas, titanium alloy components manufactured always exhibit severe springback at room temperature, which greatly restrict their application. To explore the possibility of reducing springback, rectangular lath-shaped parts with Ti-6Al-4V alloy sheet were fabricated by impact hydroforming (IHF) with self-designed equipment. Consequently, much lower springback is obtained using IHF with high strain rate than that formed by conventional stretch-bending with low strain rate. Great efforts are paid to clarify the mechanism of springback restriction under IHF. Different from traditional forming methods, more complex and high-speed interaction behavior between liquid and Ti-6Al-4V alloy sheet occurs. It considerably increases the difficulty for analyzing the deformation process of sheet under IHF. Thus, a novel solid-liquid coupling numerical simulation technology for IHF was developed. To validate the simulation accuracy, experiments with different forming processes and parameters were performed. Given the combined analysis of experimental and simulation results, it is found that distinctive forming paths are introduced between stretch-bending and IHF. Specifically, the preferred deformation region of sheet transfers from middle region for conventional stretch-bending to end regions under IHF, which mainly attributes to the unique loading behavior of liquid at high strain rate.

https://doi.org/10.1088/1757-899x/1238/1/012076

S. H. Zhang

Papers

Strengthening mechanisms, deformation behavior, and anisotropic mechanical properties of Al-Li alloys: A review

The effect of tube bending, heat treatment and loading paths on process responses of hydroforming for automobile intercooler pipe: numerical and experimental investigations

Prediction of tensile deformation behavior of Al-Li alloy 2060-T8 by computational homogenization-based crystal plasticity finite element method

Effect of novel impact hydroforming technology on the formability of Al alloys

Springback inhibition of Ti-6Al-4V sheet with impact hydroforming at room temperature