Characterization of Microstructural Evolution by Ultrasonic Nonlinear Parameters Adjusted by Attenuation Factor

The use of an acoustic nonlinear response has been accepted as a promising alternative for the assessment of micro-structural damage in metallic solids. However, the full mechanism of the acoustic nonlinear response caused by the material micro-damages is quite complex and not yet well understood. In this paper, the effect of material microstructural evolution on acoustic nonlinear response of ultrasonic waves is investigated in rolled copper and brass. Microstructural evolution in the specimens is artificially controlled by cold rolling and annealing treatments. The correlations of acoustic nonlinear responses of ultrasonic waves in the specimens corresponding to the microstructural changes are obtained experimentally. To eliminate the influence of attenuation, which was induced by microstructural changes in specimens, experimentally-measured nonlinear parameters are corrected by an attenuation correction term. An obvious decrease of nonlinearity with the increase of grain size is found in the study. In addition, the influences of material micro-damages introduced by cold rolling on the acoustic nonlinear response in specimens are compared with the ones of grain boundaries controlled by heat treatment in specimens. The experimental results show that the degradation of material mechanical properties is not always accompanied by the increase of acoustic nonlinearity generated. It suggested that the nonlinear ultrasonic technique can be used to effectively characterize the material degradations, under the condition that the variations of grain sizes in the specimens under different damage states are negligible.

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Microstructural Changes of the As-Quenched Zn-22 mass%Al-2 mass%Cu Alloy during Cold Rolling

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.43.1240 ◽

2002 ◽

Vol 43 (5) ◽

pp. 1240-1242 ◽

Cited By ~ 1

Author(s):

Héctor Javier Dorantes-Rosales ◽

Diego Israel Rivas-López ◽

Felipe Hernández-Santiago ◽

Maribel Leticia Saucedo-Muñoz ◽

Víctor Manuel López-Hirata

Keyword(s):

Cold Rolling ◽

Microstructural Changes ◽

Cu Alloy

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Post-process optimization of 3D printed poly(lactic-co-glycolic acid) dental implant scaffold for enhanced structure and mechanical properties: effects of sonication duration and power

Journal of Materials Science Materials in Medicine ◽

10.1007/s10856-021-06561-3 ◽

2021 ◽

Vol 32 (8) ◽

Author(s):

R. N. V. C. Virinthorn ◽

M. Chandrasekaran ◽

K. Wang ◽

K. L. Goh

Keyword(s):

Structural Damage ◽

Glycolic Acid ◽

Solvent Mixture ◽

Ultrasonic Waves ◽

Poly Vinyl Alcohol ◽

Covalent Bonds ◽

Process Stage ◽

Post Process ◽

3D Printed ◽

Ft Ir

AbstractWe described a technique of a post-process stage to partially remove the poly(vinyl alcohol) (PVA) binder in Poly(lactic-co-glycolic acid) (PLGA) dental scaffolds. The scaffolds were exposed to ultrasonic waves while immersed in an ethanol/acetone solvent mixture that possessed both polar and nonpolar properties. A factorial experiment was conducted in which the scaffolds were treated to three levels of sonication power (pW): 0, 20% (22 W) and 40% (44 W), and soaking duration (t): 5, 15, and 30 min. The treated scaffolds were characterized by FT-IR, optical microscopy, and mechanical (compressive) testing. FT-IR revealed that the amount of PVA decreased with increasing pW and t. Two-way ANOVA revealed that increasing pW and t, respectively, resulted in increasing scaffold surface area to volume (SVR). Sonication and solvent caused structural damage (i.e., unevenness) on the scaffold surface, but the damage was minimal at 20% pW and 30 min. The optimal values of pW and t resulting in enhanced fracture strength, strain and toughness were 20% and 30 min, respectively, which corroborated the findings of minimal structural damage. However, sonication had no significant effects on the scaffold stiffness. Mechanistic analysis of the effects of sonication predicted that the ultrasonic energy absorbed by the scaffold was sufficient to disrupt the van Der Waals bonds between the PVA and PLGA but not high enough to disrupt the covalent bonds within the PLGA. This technique is promising as it can partially remove the PVA from the scaffold, and mitigate problematic issues down the line, such as thermal degradation during sterilization, and undue delay/variability in biodegradation.

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Microstructural Evolution in a Low Carbon Steel During Cold Rolling and Subsequent Annealing

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2010.2578 ◽

2010 ◽

Vol 10 (9) ◽

pp. 6177-6181 ◽

Cited By ~ 11

Author(s):

E. Ghassemali ◽

A. Kermanpur ◽

A. Najafizadeh

Keyword(s):

Carbon Steel ◽

Cold Rolling ◽

Microstructural Evolution ◽

Low Carbon Steel ◽

Subsequent Annealing ◽

Low Carbon

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The Effect of Hydrostatic Pressure on Physical Properties and Microstructure of Spruce and Cherry

Holzforschung ◽

10.1515/hf.2000.013 ◽

2000 ◽

Vol 54 (1) ◽

pp. 83-92 ◽

Cited By ~ 11

Author(s):

Voichita Bucur ◽

Simone Garros ◽

Claire Y. Barlow

Keyword(s):

Hydrostatic Pressure ◽

Structural Damage ◽

Untreated Wood ◽

Average Density ◽

Ultrasonic Waves ◽

Ultrasonic Velocities ◽

Main Effect ◽

Natural Wood ◽

Effect Of Hydrostatic Pressure ◽

Longitudinal Ultrasonic Waves

Summary The effect of hydrostatic pressure on the density, the ultrasonic velocities and the microstructure of spruce and cherry wood has been studied. Generally speaking, under hydrostatic pressure wood becomes less heterogeneous and less anisotropic than natural wood. In spruce, crushing and buckling of the thin-walled cells in the earlywood takes place. This also has the effect of disrupting the medullary rays, which assume a zig-zag path through the structure. Cherry has a much more homogeneous structure, and the main effect of the hydrostatic pressure is compaction of the vessels by buckling of the walls. The fibres are scarcely affected by the treatment. The width of the earlywood zone decreased after the application of pressure by 26% in spruce, and by 11% in cherry. The average density was increased by the hydrostatic pressure by 26% for spruce and by 46% for cherry. The densitometric profile of spruce demonstrates significant changes following the pressure treatment, with the minimum density DMin increasing and the maximum density DMax decreasing. For cherry, the densitometric profile is shifted rather uniformly towards higher densities, and the annual ring profile is spatially slightly compacted but otherwise similar to that of untreated wood. The anisotropy of wood (expressed by the ratio of acoustic invariants) decreased by 56% for spruce and by 33% for cherry. The structural damage in spruce is predominantly found in the radial (R) direction, and this corresponds to a reduction of 73% in the velocity of the longitudinal ultrasonic waves in the radial direction, VRR. In cherry, the structural damage is mainly in the transverse, T direction. The velocity of the longitudinal ultrasonic waves in the transverse direction, VTT is reduced by 44%. The medullary rays in cherry seem to be the most important anatomical feature influencing the propagation of ultrasonic waves.

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Microstructural Evolution and Thermal Stability Characterization of a High Temperature Die Attach Lead-Free System

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/hitec-ta22 ◽

2012 ◽

Vol 2012 (HITEC) ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Rogie I. Rodriguez ◽

Dimeji Ibitayo ◽

Pedro Quintero

Keyword(s):

High Temperature ◽

Melting Point ◽

Microstructural Evolution ◽

Diffusion Mechanism ◽

Processing Temperature ◽

Mechanical And Thermal Properties ◽

Promising Alternative ◽

Free System ◽

Die Attach

There is a need for electromechanical devices capable of operating in high temperature environments (>200°C) for a wide variety of applications. Today's wide-bandgap (WBG) semiconductor based power electronics have demonstrated a potential of operating above 400°C, however they are still limited by packaging. Among the most promising alternative is the Au-Sn eutectic solder, which have been widely used due to its excellent mechanical and thermal properties. However, the operating temperature of this metallurgical system is still limited to ∼250°C owing to its melting temperature of 280°C. Therefore, a higher temperature resistant system is much needed, but without affecting the current processing temperature of ∼325°C typically exhibited in most high temperature Pb-Free solders. This paper presents the development and characterization of a fluxless die attach soldering process based on gold enriched solid liquid inter-diffusion (SLID). A low melting point material (eutectic Au-Sn) was deposited in the face of a substrate, whereas a high melting point material, gold in this instance, was deposited in its mating substrate. Deposition of all materials was performed using a jet vapor deposition (JVD) equipment where thicknesses were controlled to achieve specific compositions in the mixture. Sandwiched coupons where isothermally processed in a vacuum reflow furnace. SEM and EDS were employed to reveal the microstructural evolution of the samples in order to study the interfacial reactions of this fluxless bonding process. Mechanical characterization of the each individual intermetallic phase was achieved by nanoindentation. Differential scanning calorimetry demonstrated the progression of the SLID process by quantifying the remaining low melting point constituent as a function of time and temperature. Post-processed samples confirmed the inter-diffusion mechanism as evidenced by the formation of sound joints that proved to be thermally stable up to ∼490°C after the completion of the SLID process.

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Microstructural evolution of Ta-4%W during cold rolling

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/580/1/012041 ◽

2019 ◽

Vol 580 ◽

pp. 012041 ◽

Cited By ~ 1

Author(s):

Guoqiang Ma ◽

Andrew Godfrey ◽

Qiang Chen ◽

Guilin Wu ◽

Darcy A. Hughes ◽

...

Keyword(s):

Cold Rolling ◽

Microstructural Evolution

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Effect of particles on microstructural evolution during cold rolling of the aluminum alloy AA3104

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2009.03.183 ◽

2009 ◽

Vol 482 (1-2) ◽

pp. 264-271 ◽

Cited By ~ 32

Author(s):

Qing Liu ◽

Zongyong Yao ◽

Andrew Godfrey ◽

Wei Liu

Keyword(s):

Aluminum Alloy ◽

Cold Rolling ◽

Microstructural Evolution

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Wavelet Network Approach for Structural Damage Identification Using Guided Ultrasonic Waves

IEEE Transactions on Instrumentation and Measurement ◽

10.1109/tim.2014.2299528 ◽

2014 ◽

Vol 63 (7) ◽

pp. 1680-1692 ◽

Cited By ~ 26

Author(s):

Hossein Zamani Hosseinabadi ◽

Behzad Nazari ◽

Rassoul Amirfattahi ◽

Hamid Reza Mirdamadi ◽

Amir Reza Sadri

Keyword(s):

Structural Damage ◽

Damage Identification ◽

Ultrasonic Waves ◽

Wavelet Network ◽

Network Approach ◽

Guided Ultrasonic Waves ◽

Structural Damage Identification

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Microstructural Changes of a Creep-Damaged Nickel-Based K002 Superalloy Containing Hf Element under Different HIP Temperatures

High Temperature Materials and Processes ◽

10.1515/htmp-2014-0128 ◽

2016 ◽

Vol 35 (2) ◽

pp. 153-159 ◽

Cited By ~ 2

Author(s):

Xiaomeng Wang ◽

Yu Zhou ◽

Jian Dong ◽

Tianyou Wang ◽

Zihua Zhao ◽

...

Keyword(s):

Microstructural Evolution ◽

Temperature Increase ◽

Volume Fraction ◽

Hot Isostatic Pressing ◽

Nucleation And Growth ◽

Dissolution Process ◽

Microstructural Changes ◽

Isostatic Pressing ◽

Solute Atoms

AbstractEffects of hot isostatic pressing (HIP) temperature on the microstructural evolution of a nickel-based K002 superalloy containing Hf element after long-term service were investigated using three different soaking temperatures during HIP. The degraded γ′ precipitates represented coarse and irregular morphology after long-term service. These γ′ precipitates still were of coarse and irregular shape, but the size and volume fraction of γ′ precipitates were markedly reduced under HIP condition of 1,190°C/200 MPa/4 h, indicating that the γ′ precipitates were experiencing a dissolution process. Meanwhile, the concentrically oriented N-type γ′ rafting structure around the cavities was formed. With HIP temperature increase to 1,220°C and 1,250°C, the small-sized, cubic and regular γ′ precipitates were re-precipitated, and the concentrically oriented γ′ structure vanished. The unstable morphology induced by the nucleation and growth of γ matrix was found near the creep cavities, indicating that the solute atoms diffused inward the creep-induced cavities during HIP. However, at HIP temperature of 1,220°C and 1,250°C, a large number of blocky MC(2)-type carbides containing amounts of Hf elements were precipitated, demonstrating that HIP treatment at higher temperatures can result in the formation of a large number of blocky MC(2)-type carbides.

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