scholarly journals Effect of Hot Isostatic Pressing on Microstructures and Mechanical Properties of Ti6Al4V Fabricated by Electron Beam Melting

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 593
Author(s):  
Changyong Liu ◽  
Zhuokeng Mai ◽  
Deng Yan ◽  
Mingguang Jiang ◽  
Yuhong Dai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Grain Size ◽  
Electron Beam ◽  
Electron Beam Melting ◽  
Hot Isostatic Pressing ◽  
Phase Ratio ◽  
Lamellar Thickness ◽  
Isostatic Pressing ◽  
Β Phase

This study investigated the effects of hot isostatic pressing (HIP) on the microstructures and mechanical properties of Ti6Al4V fabricated by electron beam melting (EBM). The differences of surface morphologies, internal defects, relative density, microstructures, textures, mechanical properties and tensile fracture between the as-built and HIPed samples were observed using various characterization methods including optical metallography microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD) and tensile tests. It was found that the main effects of HIP on microstructures include—the increase of average grain size from 7.96 ± 1.21 μm to 11.34 ± 1.89 μm, the increase of α lamellar thickness from 0.71 ± 0.15 μm to 2.49 ± 1.29 μm and the increase of β phase ratio from 4.7% to 10.5% in terms of area fraction on the transversal section. The combinatorial effects including densification, increase of grain size, α lamellar thickness, β phase ratio, reduction of dislocation density and transformation of dislocation patterns contributed to the improvement of elongation and ductility of EBM-fabricated Ti6Al4V. Meanwhile, these effects also resulted in a slight reduction of the yield strength and UTS mainly due to the coarsening effect of HIP.

scholarly journals ВПЛИВ ТЕХНОЛОГІЙ ПІДВЕДЕННЯ ЕНЕРГІЇ ПРИ 3D-ПРИНТИНГУ НА СТРУКТУРУ ТА ВЛАСТИВОСТІ ДЕТАЛЕЙ ЗІ СПЛАВУ Ti-6Al-4V

2018 ◽  
pp. 86-90
Author(s):  
Алексей Александрович Педаш ◽  
Владимир Валериевич Клочихин ◽  
Тамара Александровна Митина ◽  
Валерий Григорьевич Шило
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Selective Laser Melting ◽  
Electron Beam Melting ◽  
Melt Inclusions ◽  
Hot Isostatic Pressing ◽  
Alpha Phase ◽  
Laser Melting ◽  
Isostatic Pressing ◽  
The Impact

The composition, structure and mechanical properties of samples obtained from the titanium alloy Ti-6Al-4V, by selective laser melting and electron beam melting processes regarding production of responsible aviation parts were carrying-out at present article.A comparative study of macro- and microstructure, mechanical properties has been carried out after inherent of Ti-6Al-4V heat treatment with or without prior hot isostatic pressing.It was established that the advent in specimens fractures and microstructure pores and non-melt inclusions of a granules condition obligatory hot isostatic pressing of a responsible parts when this kinds of defects significantly releases and correspondingly best complex of mechanical properties are obtained.The powders from titanium Ti-6Al-4V alloy were produce by inert gas (argon) spraying process and had a different particle sizing distribution: 20-50 microns for selective laser melting and 45-105 microns for electron beam melting.The microstructure of the specimens prepared using the studied production processes features an elongated lamellar alpha phase in the transformated epitaxially grown beta-matrix and is typical for Ti-6Al-4V alloy in a heat-treated condition.It has been noted that the lamellar alpha phase in the structure of the studied specimens after hot isostatic pressing is distinguished by larger sizes in width as compared to the specimens prior to hot isostatic pressing processing.Mechanical properties of the specimens produced by selective laser melting or electron beam melting processes meet the specification requirements. Hot isostatic pressing processing results in a remarkable improvement of the impact strength.  Authors should be pointed out that application of additive technologies in the manufacture of aerospace parts requires extensive research&development works, and testing efforts to confirm repeatability of alloy characteristics. A mandatory procedure of the production process and material approval shall be conducted to ensure compliance with aircraft flight safety standards and regulations.

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.

scholarly journals Mapping the Tray of Electron Beam Melting of Ti-6Al-4V: Properties and Microstructure

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1470 ◽  
Author(s):  
E. Tiferet ◽  
M. Ganor ◽  
D. Zolotaryov ◽  
A. Garkun ◽  
A. Hadjadj ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Beam ◽  
Fatigue Life ◽  
Electron Beam Melting ◽  
Tensile Elongation ◽  
Hot Isostatic Pressing ◽  
Lack Of Fusion ◽  
Fatigue Endurance ◽  
Printing Machine

Using an electron beam melting (EBM) printing machine (Arcam A2X, Sweden), a matrix of 225 samples (15 rows and 15 columns) of Ti-6Al-4V was produced. The density of the specimens across the tray in the as-built condition was approximately 99.9% of the theoretical density of the alloy, ρT. Tensile strength, tensile elongation, and fatigue life were studied for the as-built samples. Location dependency of the mechanical properties along the build area was observed. Hot isostatic pressing (HIP) slightly increased the density to 99.99% of ρT but drastically improved the fatigue endurance and tensile elongation, probably due to the reduction in the size and the distribution of flaws. The microstructure of the as-built samples contained various defects (e.g., lack of fusion, porosity) that were not observed in the HIP-ed samples. HIP also reduced some of the location related variation in the mechanical properties values, observed in the as-printed condition.

scholarly journals Encapsulation of Electron Beam Melting Produced Alloy 718 to Reduce Surface Connected Defects by Hot Isostatic Pressing

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1226 ◽  
Author(s):  
Yunus Emre Zafer ◽  
Sneha Goel ◽  
Ashish Ganvir ◽  
Anton Jansson ◽  
Shrikant Joshi
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Surface Defects ◽  
High Surface ◽  
Hot Isostatic Pressing ◽  
Coated Sample ◽  
Alloy 718 ◽  
Isostatic Pressing ◽  
Before And After ◽  
X Ray Computed

Defects in electron beam melting (EBM) manufactured Alloy 718 are inevitable to some extent, and are of concern as they can degrade mechanical properties of the material. Therefore, EBM-manufactured Alloy 718 is typically subjected to post-treatment to improve the properties of the as-built material. Although hot isostatic pressing (HIPing) is usually employed to close the defects, it is widely known that HIPing cannot close open-to-surface defects. Therefore, in this work, a hypothesis is formulated that if the surface of the EBM-manufactured specimen is suitably coated to encapsulate the EBM-manufactured specimen, then HIPing can be effective in healing such surface-connected defects. The EBM-manufactured Alloy 718 specimens were coated by high-velocity air fuel (HVAF) spraying using Alloy 718 powder prior to HIPing to evaluate the above approach. X-ray computed tomography (XCT) analysis of the defects in the same coated sample before and after HIPing showed that some of the defects connected to the EBM specimen surface were effectively encapsulated by the coating, as they were closed after HIPing. However, some of these surface-connected defects were retained. The reason for such remnant defects is attributed to the presence of interconnected pathways between the ambient and the original as-built surface of the EBM specimen, as the specimens were not coated on all sides. These pathways were also exaggerated by the high surface roughness of the EBM material and could have provided an additional path for argon infiltration, apart from the uncoated sides, thereby hindering complete densification of the specimen during HIPing.

Mechanical properties and low-temperature aging of tetragonal zirconia polycrystals processed by hot isostatic pressing

2003 ◽  
Vol 18 (10) ◽  
pp. 2415-2426 ◽  
Author(s):  
J. Muñoz-Saldaña ◽  
H. Balmori-Ramírez ◽  
D. Jaramillo-Vigueras ◽  
T. Iga ◽  
G. A. Schneider
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Low Temperature ◽  
Hot Isostatic Pressing ◽  
Tetragonal Zirconia ◽  
Hot Water ◽  
Full Density ◽  
Isostatic Pressing ◽  
Low Temperature Aging ◽  
Temperature Aging

The influence of grain size and density of yttria-tetragonal zirconia polycrystals (Y-TZPs) ceramics on mechanical properties and on low-temperature aging degradation (LTD) in air and in hot water was investigated. A TZP powder containing 3 mol% Y2O3 was consolidated by slip casting and densified by the sintering/hot isostatic pressing (HIP) method. Only the presintered samples that contained less than 0.15% open porosity reached near full density after HIP. The best conditions to reach full density were found to be attained by presintering and HIP both at 1400 °C. At these conditions, some of the best mechanical properties such as modulus of rupture and Weibull modulus reached 1397 ± 153 MPa and, 10.6, respectively. These values were clearly higher than those obtained from sintered bodies and samples hot isostatically pressed at 1600 °C. Aging degradation of 3Y-TZP materials can be avoided through microstructural design. Fully dense materials with a critical grain size <0.36 μm did not show any evidence of degradation after extreme aging conditions at pressurized autoclaving in hot water at 100, 200, and 260 °C for 8 h. We propose a criterion to predict degradation in air as well as in hot water for the characterized materials based on the microstructure and density control of the samples.

Simultaneous Synthesis and Sintering of Al2O3/Mo2N Composites Using Capsule-Free Nitrogen Hot Isostatic Pressing and their Characterization

2010 ◽  
Vol 62 ◽  
pp. 197-202
Author(s):  
Hirota Ken ◽  
Takaoka Katsuya ◽  
Murase Yasushi ◽  
Kato Masaki
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Hot Isostatic Pressing ◽  
Isostatic Pressing ◽  
Simultaneous Synthesis ◽  
Powder Compacts ◽  
Al2o3 Matrix

Synthesis of dense materials with the compositions of Al2O3/Mo2N=100/0 ~ 40/60 vol% has been attempted directly from Al2O3/Mo mixed raw powder compacts using capsule-free N2 hot isostatic pressing (HIP). During HIPing [1500°C/(16~20)MPa]/1h], solid/gas reaction between Mo and N2 was introduced to form Mo2N. Most sintered composites consisting of only Al2O3 and Mo2N phases reached a higher relative density than 98.0% with closed pores nevertheless capsule-free HIPing. Distribution of Mo2N particles just formed suppressed the grain growth of Al2O3 during sintering. Mechanical properties, such as bending strength (Σb), Vickers hardness (HV), fracture toughness (K1C), and other properties have been evaluated as a function of their compositions. The best mechanical values of Σb (c.a. 573 MPa), HV (c.a. 20.3 GPa) and K1C (c.a. 5.00 MPa･m1/2) were attained at the composition of Al2O3/Mo2N=90/10 vol%, due to a high density (98.6%) and small grain size of Al2O3 matrix (Gs c.a. 4.70 μm). Further addition of Mo2N reduced the sinterability of matrix grains, resulting in low densities of around 90% at the 40/60 vol% composition.

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