Article
Materials Science, Multidisciplinary
Asif Mahmud, Thinh Huynh, Le Zhou, Holden Hyer, Abhishek Mehta, Daniel D. Imholte, Nicolas E. Woolstenhulme, Daniel M. Wachs, Yongho Sohn
Summary: The study examined the mechanical properties of Ti-6Al-4V ELI alloy after post-heat treatments, showing that the alloy exhibited improved uniformity and ductility after hot isostatic pressing.
Article
Engineering, Manufacturing
Shmuel Hayun, Einat Strumza, Peri Landau, Giora Kimmel, Yaron Ganor, Ori Yeheskel
Summary: Three types of Ti-6Al-4V alloys were prepared using different powder bed fusion methods. The thermal properties of the alloys were measured, and the effects of measurement direction and processing conditions were analyzed. The results showed that the thermal expansion and thermal diffusivity were influenced by the measurement direction and the porosity of the samples. However, after correcting for porosity, the thermal properties of the alloys were similar regardless of the production method. The study also discussed the relationship between the subtle differences in the samples and the oxygen content, microstructure processing route, and preferred orientation.
ADDITIVE MANUFACTURING
(2022)
Article
Nanoscience & Nanotechnology
Matthew K. Dunstan, Matthew O. Vaughn, James D. Paramore, Brady G. Butler, Andelle D. Kudzal, Kevin J. Hemker
Summary: In laser powder bed fusion additive manufacturing of Ti-6Al-4V, the rapid cooling rates and thermal cycling result in a martensitic microstructure, which leads to high strength but low ductility. Post-processing heat treatments, such as the thermo hydrogen refinement of microstructure (THRM), can be used to decompose the martensitic microstructures and improve ductility by inducing grain refinement. This study explores the use of THRM with a hydrogen atmosphere to manipulate microstructure and enhance tensile ductility in Ti-6Al-4V produced by laser powder bed fusion. Low maximum temperatures combined with an inert globularization heat treatment can achieve tensile properties comparable to hot isostatic pressing.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Engineering, Manufacturing
Arash Soltani-Tehrani, Mahdi Habibnejad-Korayem, Shuai Shao, Meysam Haghshenas, Nima Shamsaei
Summary: This study investigates the impact of powder characteristics, particularly particle size distribution, on the microstructure, mechanical, and fatigue properties of Ti-6Al-4V specimens. The results show that particle size distribution has minimal effects on microstructure and surface roughness, but significant effects on the distribution of defects. Specimens fabricated from coarse powder exhibit improved ductility and fatigue properties compared to fine powder specimens.
ADDITIVE MANUFACTURING
(2022)
Article
Nanoscience & Nanotechnology
Meili Zhang, Chi-Ho Ng, Ali Dehghan-Manshadi, Chris Hall, Michael J. Bermingham, Matthew S. Dargusch
Summary: Super beta-transus hot isostatic pressing (HIPing) can transform columnar grains to equiaxed grains in additively manufactured Ti-6Al-4V. It is unclear whether super beta-transus HIPing can also generate isotropic microstructure and mechanical properties in high-density additively manufactured Ti-6Al-4V.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Nicholas Derimow, Jake T. Benzing, Keenan Hanson, Nikolas Hrabe
Summary: A globular alpha recrystallization has been found on the surface of net shape electron beam powder-bed fusion (PBF-EB) Ti-6Al-4V alloy parts. This recrystallization is a result of powder recovery blasting and hot isostatic pressing treatment (HIP), simulating the thermomechanical treatment required for globularization in wrought Ti-6Al-4V. The thickness of the globular surface alpha layer varies depending on the blasting intensity and the presence of surface protrusions. Controlled blasting parameters and globular surface layer thickness could potentially create tunable fatigue and wear performance.
Article
Engineering, Manufacturing
Lingxiao Zeng, Wen Hao Kan, Kun Zhang, Chao Voon Samuel Lim, Louis Ngai Sum Chiu, Shaun David Gregory, Aijun Huang
Summary: Despite the slow production speed of LPBF, a hybrid approach combining LPBF and HIP can be used to accelerate the process. This study investigates the viability of using HIP to consolidate non-accessible powder-filled cavities in an LPBF Ti-6Al-4V part. Results show that HIP can achieve excellent bonding across the shell/cavity interface, although the elongation of the cavity region is poorer.
JOURNAL OF MANUFACTURING PROCESSES
(2023)
Article
Nanoscience & Nanotechnology
Yaoxin Huo, Zhengguan Lu, Min Cheng, Jinping Fan, Junwei Qiao, Lei Xu, Ruipeng Guo, Rui Yang, P. K. Liaw
Summary: This study presents the first investigation on the dwell-fatigue behavior and damage mechanism of as-HIPed Ti-6Al-4V powder compact. The results show that the peak stress and stress ratio have significant effects on dwell fatigue behavior. A crack-initiation and propagation model based on soft-hard grain pairs has been proposed to explain the dwell-fatigue mechanism.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Engineering, Mechanical
J. S. Jesus, L. P. Borrego, J. A. M. Ferreira, J. D. Costa, A. C. Batista, C. Capela
Summary: The fatigue crack growth behavior of titanium alloy Ti-6Al-4V after Hot Isostatic Pressing through Laser Powder Bed Fusion was analyzed. Crack growth under constant amplitude loading and the transient crack growth behavior after overloads or underloads were studied. The effect of mean stress and transient delay behavior were investigated.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Engineering, Mechanical
Arash Soltani-Tehrani, John P. Isaac, Hareesh Tippur, Daniel F. Silva, Shuai Shao, Nima Shamsaei
Summary: This study investigated the effects of powder reuse and location dependency on the mechanical properties of laser powder bed fused Ti-6Al-4V Grade 5 parts. The results showed that reusing the powder improved powder flowability and packing state, but increased oxygen content. Powder reuse increased tensile strength and critical energy release rate under high strain-rate loading, but specimens in downstream locations suffered from spattering, resulting in lower fatigue performance and tensile ductility.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Nanoscience & Nanotechnology
Pushkar Prakash Dhekne, Tijmen Vermeij, Vivek Devulapalli, Suraj Dinkar Jadhav, Johan P. M. Hoefnagels, Kim Vanmeensel
Summary: The plastic deformation mechanisms of heat-treated L-PBF processed Ti-6Al-4V components were studied by in-situ uniaxial tensile loading, revealing the accommodation of higher strain in the transformed beta phase, strain accumulation in primary alpha at interface regions with lower Al content, and strain localization pathways created by needle-shaped secondary alpha precipitates.
SCRIPTA MATERIALIA
(2023)
Article
Metallurgy & Metallurgical Engineering
Yi Xiao, Li-hui Lang, Wen-cai Xu, De-xin Zhang
Summary: High-quality Ti-6Al-4V powder-solid parts were successfully fabricated using the hot isostatic pressing (HIP) process, which possessed good interfacial strength and mechanical properties.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2022)
Article
Chemistry, Physical
Terrence P. Moran, Patricio E. Carrion, Seungjong Lee, Nima Shamsaei, Nam Phan, Derek H. Warner
Summary: This study investigates the efficacy of hot isostatic pressing (HIP) in enhancing the fatigue performance of additively manufactured (AM) Ti-6Al-4V. The limitations of HIP are explored by varying the initial material state through the selection of AM system, powder chemical composition, and process parameters. It is found that the fatigue performance of HIP'd AM Ti-6Al-4V depends on the as-built quality, and differences in common material attributes cannot fully explain the observed discrepancies in performance. Furthermore, exploring HIP parameters outside of ASTM recommendations shows that a reduced temperature and high-pressure treatment significantly improve fatigue performance.
Article
Engineering, Manufacturing
Zhuoer Chen, Xinhua Wu, Chris H. J. Davies
Summary: This study demonstrates the use of surface roughness data as an evaluation tool for process variation in a commercial L-PBF machine, with factors like powder recoating, spatter generation, gas flow and heat transfer being identified as key contributors to intra-build quality inconsistency. Surface roughness was found to vary across build volume and progression, with strong impact from the orientation of inclined surfaces to the laser origin.
ADDITIVE MANUFACTURING
(2021)
Article
Engineering, Mechanical
Litton Bhandari, Vidit Gaur
Summary: The fatigue performance of the Ti-6Al-4V alloy built through laser-powder bed fusion was studied. Different post-process methods, including heat treatment, machining, and hot isostatic pressing, were explored to enhance the mechanical and fatigue properties. Machining improved the fatigue properties of the as-built samples, while heat treatment and hot isostatic pressing decreased tensile strength but increased ductility. The fatigue strength was improved with heat treatment and further enhanced by the combination of heat treatment, hot isostatic pressing, and machining.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Automation & Control Systems
Fabio Giudice, Severino Missori, Andrea Sili
Summary: This study introduces a multipoint-line thermal source model based on heat conduction to simulate the thermal effects of keyhole full penetration welding mode from high-power CO2 laser. The proposed model aims to simplify the selection of optimal process conditions.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2021)
Article
Green & Sustainable Science & Technology
Fabio Giudice, Raffaele Barbagallo, Giovanna Fargione
Summary: This paper introduces a new Design for Additive Manufacturing approach, which evaluates the energy efficiency of different design solutions for the additive process through an energy consumption model and the concept of building energy. By detailing an energy consumption model for Electron Beam Melting technology and examining the energy consumption differences in manufacturing components of different shape classes, the study offers guidance for designers in effective improvement interventions.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Chemistry, Multidisciplinary
Fabio Giudice, Andrea Sili
Summary: The proposed modeling of the thermal field allows evaluation of fusion zone composition and solidification mode to aid in selecting optimal welding parameters and preventing hot cracking. An analytical method is used to predict weld metal microstructure based on the thermal fields generated during laser beam travel on thick plates, focusing on avoiding hot cracking by predicting molten zone microstructure.
APPLIED SCIENCES-BASEL
(2021)
Article
Materials Science, Multidisciplinary
Girolamo Costanza, Fabio Giudice, Andrea Sili, Maria Elisa Tata
Summary: Researchers developed a predictive analytical model for the compressive behavior of closed-cell Al foams based on the correlation between cellular morphology and mechanical response, successfully simulating the entire compression stress-strain curve.
Article
Engineering, Multidisciplinary
Fabio Giudice, Antonio Grasso, Eugenio Guglielmino, Andrea Sili
Summary: A calculation model is proposed to assess the combined effects of hot oxidation and creep damage on the residual life of radiant tubes used in topping furnaces of petrochemical plants. The model is effective in formulating hypotheses on the tubes actual thermal history and defining the range of operating conditions that guarantee a safe return to service. It can also predict the service life span of new tubes in ideal stable operating temperature, confirming the need for scheduling periodic checks to detect the actual condition of the tubes.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2022)
Article
Polymer Science
Hossem Belhamdi, Benalia Kouini, Antonio Grasso, Cristina Scolaro, Andrea Sili, Annamaria Visco
Summary: In this study, the wear behavior of the mechanical coupling between UHMWPE and Ti6Al4V was investigated, and the addition of nanocomposite and paraffin oil was found to significantly improve the wear resistance.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Engineering, Chemical
Edoardo Arena, Giovanna Fargione, Fabio Giudice, Elisa Latona
Summary: The study aims to enhance the basic RBI approach by using IOWs analysis, offering a fully integrated dynamic risk-based methodological framework for inspection and maintenance departments to improve monitoring of critical plant parameters that could limit the reliability of pressure equipment during their life cycle.
JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES
(2022)
Article
Materials Science, Multidisciplinary
Annamaria Visco, Fabio Giudice, Eugenio Guglielmino, Cristina Scolaro, Andrea Sili
Summary: This study focused on the tribological contact between a titanium-aluminum-vanadium alloy pin and a sheet of ultra high molecular weight polyethylene. Tribometric tests revealed the specific wear rate under different lubrication conditions, and observed a compressive effect on the pin tip during the test campaign.
Article
Automation & Control Systems
Fabio Giudice, Andrea Sili
Summary: This paper presents a theoretical approach for predicting the distribution of residual stresses in welded parts using a parameterized multi-source model. The method uses analytical calculations based on the thermal field to analyze the longitudinal distribution of residual stresses. The approach is validated using the keyhole full penetration welding mode.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Annamaria Visco, Gabriella Epasto, Fabio Giudice, Cristina Scolaro, Andrea Sili
Summary: Debris formation is crucial for determining the lifespan of prosthetic joints. Potential errors can arise when measuring mass loss due to small values involved and absorption of humidity in the specimen. Accurate cleaning and drying processes can minimize these errors.
APPLIED SCIENCES-BASEL
(2023)