Characterization of Titanium Alloy Obtained by Powder Metallurgy.

Cristina Ileana Pascu,Ștefan Gheorghe,Claudiu Nicolicescu,Anca Didu,Ionuț Geonea,Nicoleta Cioateră

doi:10.3390/ma15062057

Abstract

Ti-based alloys are an important class of materials suitable especially for medical applications, but they are also used in the industrial sector. Due to their low tribological properties it is necessary to find optimal technologies and alloying elements in order to develop new alloys with improved properties. In this paper, a study on the influence of sintering treatments on the final properties of a titanium alloy is presented. The alloy of interest was obtained using the powders in following weight ratio: 80% wt Ti, 8% wt Mn, 3% wt Sn, 6% wt Aluminix123, 2% wt Zr and 1% wt graphite. Two sintering methods were used, namely two-step sintering (TSS) and multiple-step sintering (MSS), as alternatives to conventional sintering which uses a single sintering dwell time. Evolution of sample morphology, composition and crystalline structure with sintering method was evidenced. The lower values for the friction coefficient and for the wear rate was attained in the case of the sample obtained by TSS.

Highlights

Titanium has some spectacular properties, such as high toughness, low density and good corrosion resistance, making it attractive to be used most frequently in the biomedical field [1–3]
Given the previous results obtained by adding small amounts of metallic elements that allowed to obtain Ti-based alloys with improved final properties, we developed a Ti-based alloy with the following chemical composition: 80% wt
The hydrodynamic diameter of precursor mixture measured by dynamic laser scattering (DLS) can be slightly larger compared to that measured at scanning electron microscope (SEM) because DLS measures the diameter of a sphere, which has the same average diffusion coefficient as the measured particle [44]

Summary

Introduction

Titanium has some spectacular properties, such as high toughness, low density and good corrosion resistance, making it attractive to be used most frequently in the biomedical field [1–3]. Despite the very good physical and mechanical properties of titanium, the reason for its diminished area of applicability in the field of engineering is the high cost of titanium as a pure metal [4] and the difficult handling conditions, due to fine titanium powder flammability in contact with air [5] and low tribological properties [6] For these reasons, titanium-based alloys are used in industrial applications [7], such as in the aerospace [8–11], automotive [12], chemical and petrochemical industries [13], as well as electronics and electrical engineering [14]. Some researchers have found that the use of TiH2 powders can improve sintered density, induce microstructure modification, and reduce the oxygen content and cost of raw materials, compared with Ti powders [19]. Solutions were sought in the production of titanium alloys using cheaper manufacturing technologies from titanium compounds (TiO2 , TiH2 ) [20]

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