Deformation Behavior of Wrought and EBAM Ti-6Al-4V under Scratch Testing

Artur Shugurov,Sergey Martynov,Alexander Bakulin,Alexey Panin,Lyudmila Kazantseva,Svetlana Kulkova,Marina Kazachenok

doi:10.3390/met11111882

Artur Shugurov, Sergey Martynov + Show 5 more

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https://doi.org/10.3390/met11111882

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Abstract

The microstructure, mechanical properties, and deformation behavior of wrought and electron beam additive manufactured (EBAM) Ti-6Al-4V samples under scratching were studied. As-received wrought Ti-6Al-4V was subjected to thermal treatment to obtain the samples with microstructure and mechanical characteristics similar to those of the EBAM samples. As a result, both alloys consisted of colonies of α phase laths within prior β phase grains and were characterized by close values of hardness. At the same time, the Young’s modulus of the EBAM samples determined by nanoindentation was lower compared with the wrought samples. It was found that despite the same hardness, the scratch depth of the EBAM samples under loading was substantially smaller than that of the wrought alloy. A mechanism was proposed, which associated the smaller scratch depth of EBAM Ti-6Al-4V with α′→α″ phase transformations that occurred in the contact area during scratching. Ab initio calculations of the atomic structure of V-doped Ti crystallites containing α or α″ phases of titanium were carried out to support the proposed mechanism.

Highlights

Additive manufacturing (AM) has been extensively developed in the past decade exhibiting great potential for different applications in the aerospace, automotive, biomedical, power generation industries, etc. [1]
The study of scratching behavior of wrought and electron beam additive manufactured (EBAM) Ti-6Al-4V samples with similar microstructure and hardness showed that their deformation occurred via ploughing the material, which resulted in the formation of scratch grooves with pile-ups along their flanks
The samples exhibited a significant difference in their mechanical response; i.e., the penetration depth of the indenter during scratching decreased from 810 nm in the wrought sample to 660 nm in the EBAM sample

Summary

Introduction

Additive manufacturing (AM) has been extensively developed in the past decade exhibiting great potential for different applications in the aerospace, automotive, biomedical, power generation industries, etc. [1]. Ti-6Al-4V, are among the most widely used materials in the AM processes [2,3,4,5,6] This is due to the extensive use of titanium alloys in industrial applications conditioned by their superior properties such as high strength-to-weight ratio, high toughness, excellent corrosion resistance, and biocompatibility [7]. The cost of manufacturing titanium components from the mill products can be very high, since up to 80% of the material is usually consumed to generate machined swarf [8]. This explains the attraction of the additive manufacturing, which tends to produce near-net-shape components

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