Heat-assisted incremental sheet forming of TI-6AL-4V sheets

Li, Weining ORCID: 0000-0002-8844-564X (2022). Heat-assisted incremental sheet forming of TI-6AL-4V sheets. University of Birmingham. Ph.D.

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Abstract

Single point incremental forming (SPIF) is a sheet forming technique that deforms sheet materials incrementally to a designated shape. The process has shown high ability to deform low-strength materials for good geometrical accuracy and formability at room temperature. Deforming high-temperature alloys, such as Ti-6AI-4V, requires integrated heat sources to increase the ductility of the metal sheets for deformation. However, the integration of heating results in unpredictable thermomechanical behaviours on the formability, geometric accuracy, thickness distribution and surface quality. Considerable research efforts have been in developing in different heating methods and designing novel tools and analytical modelling to resolve the limitations. The current challenge remains to improve the localised and stable heating and functional tool design to reduce the thermal expansion and friction at the tool-surface contact area and the analysis of relationship between thermal and mechanical effects. This PhD research aims to develop and improve the induction heating-assisted SPIF system for Ti-6AI-4V sheets in tool design, lubrication, tool path optimisation and numerical analysis. Total four research methods include the study of microstructural and mechanical properties for low temperature (600 ℃ and 700 ℃) deformation using Zener-Hollomon parameter (Z-parameter). A novel tool design with water-cooling lubricant system to assist lubricant service. A combination of crystal plasticity finite element simulation method (CPFEM), representative volume element (RVE) and cellular automata (CA) to predict the grain orientation, crystal texture and grain size evolution in experimental scale and microstructure. A radial basis function (RBF) artificial neural network to optimise the tool path for improvements of geometric accuracy and surface quality above beta-transus (950 ℃) temperature.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):