Study of the Effect of the Floating Die Compaction on Mechanical Properties of Titanium Foams

Sergio Sauceda,Claudio Aguilar,Ernesto Chicardi,Guilherme O Neves,Christopher Salvo,Luis Béjar,Sheila Lascano

doi:10.3390/met10121621

Abstract

Titanium (Ti) and its alloys are used for biomedical applications because of their high resistance to corrosion, good strength-to-weight ratio, and high fatigue resistance. However, a problem that compromises the performance of the material is the mismatch between Young’s modulus of Ti and the bone, which brings about stress shielding. One strategy that has been investigated to reduce this difference is the manufacture of Ti-based foams, using powder metallurgy (PM) methods, such as the space-holder technique. However, in the uniaxial compaction, both non-uniform density distribution and mechanical properties remain because of the compaction method. This work studies the influence of compaction by adopting a floating-action die related to a single-action die (SAD), on the density of green and sintered Ti foams with porosities around 50 vol.% characterized by optical microscopy, ultrasound analysis, compression tests, and microhardness. The compaction process employing a floating-action die generates Ti foams with a higher density up to 10% with more control of the spacer particle added compared to the single-action die. Furthermore, compaction method has no relevant effect on microhardness and Young’s modulus, which allows getting better consolidated samples with elastic modules similar to those of human bone.

Highlights

Titanium (Ti) is one of the metallic elements with the greatest development in recent decades because of its favorable strength-to-weight ratio, low thermal expansion coefficient, and good corrosion resistance [1]
The effect of the content of spacer particles added and the two compaction methods used on the densities is analyzed
For the green samples, the variation in density between both compaction methods is statistically significant (Pvalue < 0.05), being higher in the foams with floating action. It is the result of the movement of die resulting from friction between the walls of the die and the powder particles which causes a relative displacement between the die and lower punch, distributing the total load between the upper and lower punch

Summary

Introduction

Titanium (Ti) is one of the metallic elements with the greatest development in recent decades because of its favorable strength-to-weight ratio, low thermal expansion coefficient, and good corrosion resistance [1]. For these aspects, titanium and its alloys have been used in the automotive, aerospace, marine, biomedical implant industries, among others [2,3]. Concerning to biomaterials, Ti and its alloys are one of the most suitable materials for their excellent behavior in the human body, derived from their outstanding balance between mechanical properties and biocompatibility [4].

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Results

Conclusion