A Study of Improving the Formability of the Commercial Pure Titanium Foils

Author ORCID Identifier

Jenn-Terng Gau:https://orcid.org/0000-0002-8882-8659

Publication Title

Journal of Engineering Materials and Technology, Transactions of the ASME

ISSN

00944289

E-ISSN

43901

Document Type

Article

Abstract

In order to obtain the optimum forming process for commercial pure titanium grade 2 foils, a series of tensile tests and micro scale limited dome height (µ-LDH) tests at four temperatures, and meso scale limited dome height tests (meso-LDH) with three punch speeds were conducted on the as-received foils with a thickness of 75 µm. The effects of temperature, geometry, and high-velocity impact were investigated to understand their influences on the formability of the foils. It has been found in the tensile tests that the formability can be improved by elevating temperatures; this has been validated by the µ-LDH tests. Based on forming limit diagrams (FLDs) of the meso-LDH specimens, the high-velocity impact forming process results in not only much better formability but also more uniform thickness distributions than the quasi-static. By analyzing the fractographical scanning electron microscope (SEM) pictures of the meso-LDH specimens, it has been proven that the formability of the foils by using high-velocity impact process is superior to the conventional process. Furthermore, high-velocity impact causes forming limit curve (FLC) to shift in the upper right direction on the right-hand side of FLD. Therefore, it is suggested forming the foils by using high-velocity impact forming process at the elevated temperature for obtaining a better formability and more uniform thickness distribution. It is also recommended to make the radius of the LDH hemisphere punch close to the smallest feature of the designed products for obtaining more accurate FLCs.

Publication Date

7-1-2020

DOI

10.1115/1.4046368

Keywords

Materials processing, Mechanical behavior, Plastic behavior

Department

Department of Mechanical Engineering

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