Introduction to Aerospace Materials

4

Strengthening of metal alloys

4.1 Introduction

Metal alloys used in aircraft structures and engines must have high mechanical properties to ensure weight-efficiency. It is essential that metals used in aircraft have sufficient strength to avoid permanent deformation and damage under the structural, aerodynamic and other loads experienced during flight. The mechanisms by which aerospace metals achieve their high strength are complex. Various mechanisms occur at the atomic, nanometre, microstructural and millimetre scales and these control the strength properties, as shown in Fig. 4.1 for the aluminium alloys used in an aircraft wing. Without these strengthening mechanisms occurring at different length scales, metals would be too soft and susceptible ...