Investigating the Influence of Step Size and Tool Diameter on the Microstructure of Incrementally Formed Commercially Pure Titanium

Abstract

This study examines how the microstructure of pure titanium is affected by Single Point Incremental Forming (SPIF) factors, such as step sizes (0.2, 0.4, 0.6 mm) and tool diameters (6, 10, 14 mm). According to the research, increasing step sizes cause more material to deform with each stride, which increases the accumulation of strain over shorter distances. By encouraging grain refinement and resulting in smaller, more evenly dispersed grains, this strain can improve mechanical qualities. Furthermore, localized heating is produced by the increased friction brought on by bigger step sizes, which further influences microstructural alterations.

The results show that, with respect to tool diameter, larger tools provide greater friction, which might lead to localised heating and encourage grain recrystallisation. This therefore has an impact on the material's residual stresses, which are crucial to the final microstructure. The study highlights the connection between tool diameter and microstructural evolution by analysing four different sections from each sample and observing significant changes in grain size and distribution along the sample wall. The findings highlight how crucial it is to optimise SPIF parameters in order to enhance the material's performance properties.

The analysis of fracture behaviour sheds light on the change from brittle to ductile fracture. SEM study of the fracture surfaces demonstrates that the number of pits increases as tool diameter and step size decrease, influencing the fracture behaviour.