Influence of hot isostatic pressing on the performance of aluminum alloy fabricated by ultrasonic additive manufacturing

Gussev, Maxim N.; Sridharan, Niyanth; Thompson, Z. T.; Terrani, Kurt A.; Babu, S. S.

doi:10.1016/j.scriptamat.2017.10.004

Cited by 66 publications

(29 citation statements)

References 21 publications

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“…The equiaxed grains of 5‐10 and 5 µm in size were observed in the HIP‐treated water‐ and gas‐atomized L‐PBF parts, respectively. According to Hall‐Petch strengthening mechanism, the decrease in the grain size could have contributed to the increase in yield strength of water‐ and gas‐atomized L‐PBF parts after the HIP treatment.…”

Section: Resultsmentioning

confidence: 99%

Microstructures, properties, and applications of laser sintered 17‐4PH stainless steel

Irrinki

Nath

Alhofors³

et al. 2019

J Am Ceram Soc

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The effects of hot isostatic pressing (HIP) on the densification, mechanical properties, and microstructures of laser‐powder bed fusion (L‐PBF) 17‐4 PH stainless steel parts were studied using gas‐ and water‐atomized powders. The % theoretical density, ultimate tensile strength, yield strength, elongation, and hardness of as‐printed and HIP‐ed L‐PBF parts were sensitive to energy density and starting powder shape, size, and type. At low‐energy densities of 64 and 80 J/mm3, densification was significant for water‐atomized L‐PBF parts when subjected to HIP treatment and density increased from 90% to 97%. For all the energy densities, the gas‐atomized L‐PBF parts after the HIP treatment showed significantly higher tensile strength, yield strength, and hardness when compared to water‐atomized L‐PBF parts properties. At low‐energy densities of 64 and 80 J/mm3, long columnar grains in the as‐printed L‐PBF parts did not change significantly after the HIP treatment whereas the columnar grains present in as‐printed gas‐atomized L‐PBF parts completely disappeared when subjected to HIP treatment. However, at high‐energy densities of 84 and 104 J/mm3, the columnar grains in as‐printed L‐PBF gas‐ and water‐atomized L‐PBF parts were changed to equiaxed grains and showed a higher level of homogenization when subjected to HIP treatment. This variation in grains and grain size had significantly affected the yield strength and elongation of HIP‐treated gas‐ and water‐atomized L‐PBF parts.

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Section: Resultsmentioning

confidence: 99%

Microstructures, properties, and applications of laser sintered 17‐4PH stainless steel

Irrinki

Nath

Alhofors³

et al. 2019

J Am Ceram Soc

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“…UAM can produce good quality functional components but these components are sometimes prone to defects and delamination typical to UAM. Several studies focus on developing optimal process parameters for UAM and then eliminating defects through post-weld treatments [11,23,27,94,103,113,114,115,116]. To form a good bond, there must be enough power input into the ultrasonic weld while at the same time ensuring that already bonded interfaces are not pulled apart due to excessive vibration or power input [103].…”

Section: Sensitivity Analysis On the Inversion Scheme Indicates That mentioning

confidence: 99%

“…Both Type-1 and Type-2 defects in UAM components need to be eliminated either through improving the process or healed after manufacturing, so that UAM components can be used for structural applications [94,114]. Post-process heat treatment of UAM components was shown to be effective in increasing bond quality and reducing Type-1 defects, but heat treatment can't fix Type-2 defects.…”

Section: Sensitivity Analysis On the Inversion Scheme Indicates That mentioning

confidence: 99%

“…have found that %LWD is not a good measure of the bond strength since it does not consider kissing bonds or tightly closed regions. A better qualitative mechanism was suggested[94] based on a pull out tensile test followed by measurement of the fractured surface to analyze the % bonded region. It was argued that there is a definite presence of tightly closed surfaces in UAM that cannot be observed with an optical microscope, since only after tensile testing will these kissing bonds be visible.…”

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confidence: 99%

“…It was argued that there is a definite presence of tightly closed surfaces in UAM that cannot be observed with an optical microscope, since only after tensile testing will these kissing bonds be visible. It was further explored how there could be what appears to be complete metallurgical bonding but on pull out tensile tests along the build direction the measured UTS could be as low as 15% that of a solid wrought material[94]. The reasoning for the same was argued to be the presence of micro-voids that form upon the application of a small amount of stress.…”

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confidence: 99%

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Ultrasonic nondestructive evaluation of metal additive manufacturing.

Nadimpalli¹

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Metal Additive Manufacturing (AM) is increasingly being used to make functional components. One of the barriers for AM components to become mainstream is the difficulty to certify them. AM components can have widely different properties based on process parameters. Improving an AM processes requires an understanding of processstructure-property correlations, which can be gathered in-situ and post-process through nondestructive and destructive methods. In this study, two metal AM processes were studied, the first is Ultrasonic Additive Manufacturing (UAM) and the second is Laser Powder Bed Fusion (L-PBF). The typical problems with UAM components are inter-layer and inter-track defects. To improve the UAM process, an in-situ quality evaluation technique was desired. Several NDE techniques were tested in a lab environment before ultrasonic NDE was chosen as a practical, robust, and cost-effective NDE tool. An in-situ monitoring setup was designed and built on an UAM system. NDE results showed interesting features that were simulated through analytic and finite element wave-propagation models. AM layers with defects were characterized as an intact layer and a finite interfacial stiffness spring. The spring stiffness vi coefficient is a quality parameter that was used to characterize AM layers through a modelbased inversion method. In-situ and post-process NDE provided an understanding of defect generation and propagation in UAM. A novel solid-state repair mechanism based on Friction Stir Processing (FSP) was proposed and demonstrated. The quality of L-PBF components depends on several factors including laser power, scan speed, hatch spacing, layer thickness, particle shape/size distribution and other build conditions. Developing process parameters for a new material is an expensive and complex optimization problem. Post-process ultrasonic NDE tests revealed that the model-based insitu quality monitoring developed for UAM is also applicable to L-PBF Additive Manufacturing. A similar NDE setup was designed and installed on an open-architecture L-PBF system. A layer-by-layer bond quality evaluation demonstrates the ability to detect good-quality bonds hidden behind poor-quality regions for Inconel 625 alloy. A costeffective, process parameter development methodology has been proposed and demonstrated. vii TABLE OF CONTENTS

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Influence of Isostatic Pressure on the Superconducting Performance of Nb₃Al Prepared by Low‐Temperature Sintering

Zhao

et al. 2019

Physica Status Solidi (b)

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The influence of isostatic sintering pressure on the superconducting performance of Nb3Al prepared by powder metallurgy is investigated. It is found that its superconducting transition temperature (Tc) and critical current density ( Jc) are both improved with the increase in sintering pressure. Specifically, the Tc of the 180 MPa sintered sample reaches nearly 16.2 K, and its Jc is up to 1.1 × 104 A cm−2 (4.2K, 5T), an order of magnitude higher than that of the ambient sintered sample. The Nb/Al in the Nb3Al superconducting phase closer to the stoichiometric ratio of 3:1 in the pressure sintered samples is responsible for the increase in Tc; meanwhile, the reduced sintering micropores, refined grains, and more dislocations in the pressure sintered samples all contribute to the enhancement of their Jc.

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Influence of hot isostatic pressing on the performance of aluminum alloy fabricated by ultrasonic additive manufacturing

Cited by 66 publications

References 21 publications

Microstructures, properties, and applications of laser sintered 17‐4PH stainless steel

Microstructures, properties, and applications of laser sintered 17‐4PH stainless steel

Ultrasonic nondestructive evaluation of metal additive manufacturing.

Influence of Isostatic Pressure on the Superconducting Performance of Nb₃Al Prepared by Low‐Temperature Sintering

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Influence of hot isostatic pressing on the performance of aluminum alloy fabricated by ultrasonic additive manufacturing

Cited by 66 publications

References 21 publications

Microstructures, properties, and applications of laser sintered 17‐4PH stainless steel

Microstructures, properties, and applications of laser sintered 17‐4PH stainless steel

Ultrasonic nondestructive evaluation of metal additive manufacturing.

Influence of Isostatic Pressure on the Superconducting Performance of Nb3Al Prepared by Low‐Temperature Sintering

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Influence of Isostatic Pressure on the Superconducting Performance of Nb₃Al Prepared by Low‐Temperature Sintering