Influence of sheet conditions on the formability of aerospace materials at room temperature

Project aim

This project seeks to establish the impact of deformed edges on the formability of sheet titanium. It also aims to assess the effect of surface roughness on surface quality and forming limit of titanium as well as establishing the lubrication mechanism during forming at room temperature.

Project background

Due to the specific forming conditions required for low-temperature sheet forming (high forming forces), the materials become susceptible to surface defects. It is also known that the surface roughness of sheets has an enormous impact on their formability. Surface roughness results in premature nucleation of micro-cracks during forming and the subsequent failure of the part. Also, uniform distribution of surface features is known to influence the forming properties positively. However, relevant literature on the effect of surface conditions on the forming behaviour of titanium is scanty. Hence, understanding the effect of the types of single defects, their orientation, and distribution over titanium parts formability will be vital towards further future developments in the industry. This will help inform the optimisation of forming regimes as well as clarify the requirements of supplied sheets. Poor lubrication of titanium is also one of the major causes of surface defects in cold forming. Understanding the lubrication regime occurring during room temperature forming process will help improve the efficiency of forming operations and reduce die wear.