Challenges in additive manufacturing of high-strength aluminium alloys and current developments in hybrid additive manufacturing

TLDR

Additive manufacturing enables rapid, complex part production and is widely used in aerospace, where high‑strength aluminium alloys are prized for their strength‑to‑weight and stiffness‑to‑weight ratios, yet their application remains constrained by persistent defects. This review examines the current state of additive manufacturing for high‑strength aluminium alloys in aerospace applications. It discusses defects in 2xxx and 7xxx aluminium alloys and evaluates recent hybrid additive manufacturing techniques designed to reduce or eliminate these defects.

Abstract

Additive Manufacturing (AM) processes, also known as 3D printing, enable geometrically complex parts to be produced layer by layer on the basis of three-dimensional (3D) data generated either by scanning physical objects or using design software. Compared to conventional manufacturing processes, AM offers the elimination of production steps, allowing rapid and relatively easy prototyping of physical objects from 3D model designs, and reproduction of existing objects. Over the last two decades, AM processes have become widespread for the manufacturing of complex-shaped components in numerous industrial sectors, one of their main areas of application being in the aerospace industry. This sector makes extensive use of high-strength aluminium alloys because of their high strength-to-weight and stiffness-to-weight ratios and excellent machinability. However, the applicability of AM processes to high-strength aluminium alloys is still limited by the presence of several types of non-negligible issues and defects in additively manufactured (AMed) aluminium components. Over the years, significant research efforts have been directed at minimising or eliminating these defects and thereby expanding the range of applications of AM in high-strength aluminium alloys. This paper reviews the state of the art in AM of high-strength aluminium alloys for aerospace. The focus is on defects and issues in AMed 2xxx and 7xxx series alloys and recent developments in novel hybrid AM processes to minimise or eliminate the defects.