Microstructures of Electron Beam Melted (EBM) Biomaterial Ti-6Al-4V

2008 ◽  
Vol 1132 ◽  
Author(s):  
Adnan Safdar ◽  
Liu-Ying Wei
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Layer Structure ◽  
Processing Parameters ◽  
Optical Microscope ◽  
Solid Samples ◽  
Direction Parallel ◽  
Β Phase ◽  
Shape Structure ◽  
Columnar Grains

ABSTRACTTi-6Al-4V alloy is an attractive biomaterial. The current work evaluates the microstructures of the solid and net-shape Ti-6Al-4V alloy produced by Electron Beam Melting (EBM) system using SEM/EDX and optical microscope. The microstructures are influenced by the cooling rate, processing parameters of the EBM system and re-heating of the existing layer during the melting of subsequent layers. Layer structure and columnar grains have been observed, with growing direction parallel to the built direction. The interior of these grains consists of alternating α / β phases. The β phase in the colonies resembles rod shape embedded in the α platelet. Along the grain boundaries more or less continuous α layers were observed. In comparison to solid samples uneven surfaces and pores were seen in the net shape structure. Microhardness evaluation of the EBM produced alloys was also carried out and compared with conventionally produced alloys.

scholarly journals Tailoring Microstructure and Mechanical Properties of Additively-Manufactured Ti6Al4V Using Post Processing

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 658
Author(s):  
Yaron Itay Ganor ◽  
Eitan Tiferet ◽  
Sven C. Vogel ◽  
Donald W. Brown ◽  
Michael Chonin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Fatigue Resistance ◽  
Electron Beam Melting ◽  
High Reliability ◽  
National Laboratory ◽  
Post Processing ◽  
Proof Stress ◽  
Β Phase ◽  
Microstructure And Mechanical Properties

Additively-manufactured Ti-6Al-4V (Ti64) exhibits high strength but in some cases inferior elongation to those of conventionally manufactured materials. Post-processing of additively manufactured Ti64 components is investigated to modify the mechanical properties for specific applications while still utilizing the benefits of the additive manufacturing process. The mechanical properties and fatigue resistance of Ti64 samples made by electron beam melting were tested in the as-built state. Several heat treatments (up to 1000 °C) were performed to study their effect on the microstructure and mechanical properties. Phase content during heating was tested with high reliability by neutron diffraction at Los Alamos National Laboratory. Two different hot isostatic pressings (HIP) cycles were tested, one at low temperature (780 °C), the other is at the standard temperature (920 °C). The results show that lowering the HIP holding temperature retains the fine microstructure (~1% β phase) and the 0.2% proof stress of the as-built samples (1038 MPa), but gives rise to higher elongation (~14%) and better fatigue life. The material subjected to a higher HIP temperature had a coarser microstructure, more residual β phase (~2% difference), displayed slightly lower Vickers hardness (~15 HV10N), 0.2% proof stress (~60 MPa) and ultimate stresses (~40 MPa) than the material HIP’ed at 780 °C, but had superior elongation (~6%) and fatigue resistance. Heat treatment at 1000 °C entirely altered the microstructure (~7% β phase), yield elongation of 13.7% but decrease the 0.2% proof-stress to 927 MPa. The results of the HIP at 780 °C imply it would be beneficial to lower the standard ASTM HIP temperature for Ti6Al4V additively manufactured by electron beam melting.

Microstructures and Hardness Properties for β-Phase Ti–24Nb–4Zr–7.9Sn Alloy Fabricated by Electron Beam Melting

2013 ◽  
Vol 29 (11) ◽  
pp. 1011-1017 ◽  
Author(s):  
J. Hernandez ◽  
S.J. Li ◽  
E. Martinez ◽  
L.E. Murr ◽  
X.M. Pan ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Β Phase

Characterization and Corrosion Behaviour Study on Biocompatible Ti-6Al-4V Component Fabricated by Electron Beam Melting

2015 ◽  
Vol 22 ◽  
pp. 63-75 ◽  
Author(s):  
D. Devika ◽  
Soumya Shekhar Dass ◽  
Suneel Kumar Chaudhary
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Corrosion Behaviour ◽  
Optical Microscope ◽  
Structural Features ◽  
Polarization Measurement ◽  
Surface Oxide Layer ◽  
Fluid Environment ◽  
Behaviour Study ◽  
Phase Characterization

Ti-6Al-4V biocompatible material to be used as an implant, fabricated by Electron Beam Melting, was investigated for mechanical properties viz. hardness, grain size and porosity. Phase characterization was analysed by X-ray diffraction; morphological and micro structural features were assessed by Scanning Electron Microscopy and Optical Microscope respectively. The as-produced Electron beam melted Ti-6Al-4V sample had increased surface roughness and a thick surface oxide layer. The corrosion behaviour in simulated body fluid environment was compared for wrought and Electron beam melted Ti-6Al-4V samples by performing anodic polarization measurement using sequencer computer controlled potentiostat. The Electron beam melted sample had the corrosion rate of 0.0148 mils per year and wrought sample had 0.0196 mils per year.

scholarly journals Freeform Fabrication of Titanium Aluminide via Electron Beam Melting Using Prealloyed and Blended Powders

2007 ◽  
Vol 2007 ◽  
pp. 1-4 ◽  
Author(s):  
Denis Cormier ◽  
Ola Harrysson ◽  
Tushar Mahale ◽  
Harvey West
Keyword(s):  
Electron Beam ◽  
High Temperature ◽  
Intermetallic Compound ◽  
Titanium Aluminide ◽  
Electron Beam Melting ◽  
Processing Parameters ◽  
Reaction Synthesis ◽  
Prealloyed Powder ◽  
Freeform Fabrication ◽  
Temperature Performance

Titanium aluminide (TiAl) is an intermetallic compound possessing excellent high-temperature performance while having significantly lower density than nickel-based superalloys. This paper presents preliminary results of experiments aimed at processing TiAl via the electron beam melting (EBM) process. Two processing routes are explored. The first uses prealloyed powder, whereas the second explores controlled reaction synthesis. Issues such as processing parameters, vaporization of alloying elements, microstructure, and properties are discussed.

Effect of processing parameters of electron beam melting machine on properties of Ti-6Al-4V parts

2016 ◽  
Vol 22 (3) ◽  
pp. 609-620 ◽  
Author(s):  
Dana H. Abdeen ◽  
Bruce R. Palmer
Keyword(s):  
Surface Roughness ◽  
Electron Beam ◽  
Process Parameters ◽  
Electron Beam Melting ◽  
Processing Parameters ◽  
Beam Current ◽  
Exterior Surface ◽  
Content Type ◽  
Critical Pitting Temperature ◽  
Model Equations

Purpose This paper aims to study the effect of processing parameters of an electron beam melting (EBM) machine on the surface roughness, critical pitting temperature and density of Ti-6Al-4V parts produced from the EBM machine. Design/methodology/approach In this study, statistically designed experiments were used to manufacture Ti-6Al-4V samples in the EBM machine under different process parameters of beam current, beam speed and offset focus. Surface roughness was measured for as-built samples using a 3D profilometer. Then, a potentiostatic test was conducted under 2.40 V vs saturated calomel electrode to determine the critical pitting temperature (CPT) in 3.5 per cent mass NaCl solution for the samples of different processing parameters. Next, density was measured for these samples. Finally, model equations were established to relate EBM’s process parameters to measured properties of surface roughness, CPT and density. Findings Results showed that offset focus had the main influence on surface roughness more than the beam current and the beam speed. Changing processing parameters did not affect corrosion behavior of EBM Ti-6Al-4V as CPT did not vary widely, although a slight effect on CPT values obtained from the beam current and the beam speed. Density was greatly affected by the offset focus more than the other parameters. It can be concluded that uniform and precise measurements of roughness and density are not achievable through this machine; only a range of these properties can be attained. Originality/value EBM machine produces 3D parts in a layer-based building process under high temperature and vacuum atmosphere. Due to the manufacturing technique and conditions, the resulting object has irregularities on the exterior surface and voids that are formed within the part, both of which affect samples’ properties like surface roughness, CPT and density. This study established model equations that can relate parts’ properties to processing parameters so that parts of specific properties are obtained to fit the application they are used for. For each property, ANOVA fits vs linear energy were also obtained.

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