Tensile properties of α-titanium alloys at elevated temperatures

Tarik Nawaya,Axel Von Hehl,W.n Beck

doi:10.1051/matecconf/202032104016

Abstract

Hot-deep drawing is an innovative processing technology to produce complex shaped sheet metal components with constant wall thickness from high-strength lightweight materials. For some aerospace and automotive applications oxidation resistance at medium to high temperatures is an important aspect. In terms of this titanium α-alloys are often used due to their balanced relation of strength and oxidation resistance. In the presented study the stress-strain characteristics of several α-titanium alloys were determined at ambient and elevated temperatures by means of hot tensile tests. Besides the commercially pure Titanium alloy ASTM-Grade 4, two novel α-titanium alloys were investigated. Regarding the hot forming properties a comparison with α-β Ti-6Al-4V alloy was conducted. The hot tensile tests were carried out by means of a particular forming dilatometer type “Gleeble 3500” at 400, 500, 600, 650, 700 and 800 °C. The test showed favorable peak plasticity for all α-alloys at the temperature range between 600 and 650 °C in contrast to lower or higher temperatures. All samples were metallographically characterized.Key words: titanium α-alloys, hot tensile properties, elevated temperatures, Gleeble 3500.

Highlights

Titanium alloys provide both a high absolute and a high density specific strength along with a good to excellent corrosion resistance at low and at high temperatures
Since α-alloys have a good responsivity to the stress relief [2], they are suitable for novel processing approaches like the so-called hot creep forming that is a hot deep drawing followed by a stress relief stage to prevent from spring back [4,5]
A distinct elastic limit is noticed for all alloys, which is typical for titanium alloys

Summary

Introduction

Titanium alloys provide both a high absolute and a high density specific strength along with a good to excellent corrosion resistance at low and at high temperatures. These alloys are not able to be phase hardened owing to the lack of β phase For this reason, their application is wide spread in applications, such as medical implants, undersea stuff and sport goods, where high strength is not the major needed property, but enhanced juz7hcorrosion stability is mainly demanded [2, 3]. On the other hand, heating titanium sheets to a higher temperature causes the formation of detrimental α-case in the surface layer by diffusion, which affects the late fatigue properties of the part tremendous This has been studied in [6] and a statement about the best forming temperature for some αtitanium alloys were made.

Methods

Results

Discussion

Conclusion