Degradation Mechanisms of Underfills Subjected to Isothermal Long-Term Aging From 150°C to 200°C

2020 ◽  
Author(s):  
Pradeep Lall ◽  
Yunli Zhang ◽  
Haotian Wu ◽  
Ed Davis ◽  
Jeff Suhling
Keyword(s):  
High Temperature ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Uniaxial Tensile ◽  
Cross Section Area ◽  
Section Area ◽  
Before And After ◽  
Damage Tolerant ◽  
High Temperature Operation

Abstract FCBGAs are finding applications in automotive underhood environments where they may be subjected to sustained temperatures of 125–200°C for sustained periods during operation. While, FCGBAs have been previously used in consumer applications where operating temperatures typically range in 55–85°C, relatively little is known on methods to design damage-tolerant packages in automotive underhood environments. There is insufficient information on plastic encapsulated electronic components capable of surviving high temperatures for long periods (> 100,000 hours). In this paper, four different types of underfills has been cured and aged. Mechanical tests have been performed on all the four types of underfills too understand the degradation in properties under extended high temperature operation. Uniaxial tensile tests are conducted to study the elastic modulus, ultimate tensile strength and percentage elongation of the underfills. After uniaxial tensile tests, Optical Microscope, SEM and EDS are applied to study the microstructure behaviors of the cross-section area of the underfills. The experimental results are compared before and after aging tests, including pristine, 30 days, 60 days, 90days, 120 days and 240 days. The research focuses on microstructure-property-processing-performance relationships, building the relation between the microstructure evolution and macro-mechanical properties. Reliability physics of high temperature degradation of packaging material is studied.

scholarly journals Uniaxial Tensile Behavior of Carbon Textile Reinforced Mortar

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 374 ◽  
Author(s):  
Fen Zhou ◽  
Huanhui Liu ◽  
Yunxing Du ◽  
Lingling Liu ◽  
Deju Zhu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Bond Strength ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Tensile Behavior ◽  
Reinforcement Ratio ◽  
Steel Fibers ◽  
Uniaxial Tensile ◽  
Textile Reinforced Mortar

This paper investigates the effects of the reinforcement ratio, volume fraction of steel fibers, and prestressing on the uniaxial tensile behavior of carbon textile reinforced mortar (CTRM) through uniaxial tensile tests. The results show that the tensile strength of CTRM specimens increases with the reinforcement ratio, however the textile–matrix bond strength becomes weaker and debonding can occur. Short steel fibers are able to improve the mechanical properties of the entire CTRM composite and provide additional “shear resistant ability” to enhance the textile– matrix bond strength, resulting in finer cracks with smaller spacing and width. Investigations into the fracture surfaces using an optical microscope clarify these inferences. Increases in first-crack stress and tensile strength are also observed in prestressed TRM specimens. In this study, the combination of 1% steel fibers and prestressing at 15% of the ultimate tensile strength of two-layer textiles is found to be the optimum configuration, producing the highest first-crack stress and tensile strength and the most reasonable multi-cracking pattern.

Transverse Superplastic Deformation of Laser Welded Ti-6Al-4V Sheet

2011 ◽  
Vol 291-294 ◽  
pp. 1440-1443 ◽  
Author(s):  
Dong Hai Cheng ◽  
Ye Ping Zhou ◽  
Qiang Wei ◽  
Yi Ping Chen ◽  
De An Hu
Keyword(s):  
Strain Rate ◽  
Weld Joint ◽  
Superplastic Deformation ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Weld Bead ◽  
Uniform Deformation ◽  
Before And After ◽  
Acicular Structure

Uni-axial hot tensile tests were used to investigate the transverse superplastic deformation of laser welded Ti-6Al-4V sheet. Microstructures of the weld bead before and after superplastic deformation were observed by optical microscope. The maximal deformation of 46% was obtained on weld joint at strain rate of 10−2s−1 and temperature of 1173K. A coefficient K was introduced to evaluate the non-uniform deformation of weld joint. After superplastic deformation the microstructure of weld bead transformed into lamellas from original acicular structure.

scholarly journals Study for Performance Increase of a Extractor Device by Steel Replacement of AISI 304 Steel for AISI 420 Steel

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 280
Author(s):  
Francisco Alves de Lima Júnior ◽  
Ricardo Artur Sanguinetti Ferreira ◽  
Rômulo Rocha de Araújo Lima
Keyword(s):  
Stainless Steel ◽  
Service Life ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Uniaxial Tensile ◽  
Manufacturing Cost ◽  
Aisi 304 ◽  
Aisi 420 ◽  
Hardness Tests ◽  
Steel Aisi

The performance of an extractor device used in the food industry was studied from the development of structural analysis through computational modeling based on finite elements. These analyses considered the mechanical properties of AISI 304 and 420 stainless steels, in addition to the tribological aspects of the device in operation. Initially, uniaxial tensile tests were carried out according to the ABNT NBR 6892 standard and hardness tests were carried out according to ASTM E384, E92, and E18 standards. From the mechanical tests, structural analyses were carried out numerically on each of the components of the extractor device. After analyzing all the components, the device was assembled to be tested in operation. The wear and service life of devices made from these two materials were evaluated. From this study, it could be concluded that the extractor device made with AISI 420 stainless steel, in addition to having a lower manufacturing cost, suffered less wear and had an increase in service life of up to 650% compared to the extractor device made with steel stainless steel AISI 304.

The Microstructure and Elements Distribution of High-Chiromium Hypereatectoid Steel by High-Temperature Homogenization

2013 ◽  
Vol 652-654 ◽  
pp. 975-980 ◽  
Author(s):  
Jin Man ◽  
Yi Tao Yang ◽  
Guang Jie Shao
Keyword(s):  
High Temperature ◽  
Steel Ingot ◽  
Segregation Ratio ◽  
Optical Microscope ◽  
Chromium Steel ◽  
Eds Analysis ◽  
Before And After ◽  
Composition Segregation ◽  
Temperature Homogenization ◽  
Scanning Electron

The temperature range of high-temperature homogenization was determined by phase diagram calculation and the critical overburning temperature of chromium hypereatectoid steel was measured by DSC. The Comparison of microstructures and element segregation before and after homogenized treatment were investigated for chromium steel ingot by means of optical microscope, scanning electron microscopy and EDS. The results show that the liquation carbides and composition segregation are improved after the chromium steel was treated by high-temperature homogenization. According to the results of EDS analysis and segregation ratio calculation for the samples homogenized at different temperature, the optimum homogenization process for Cr steel is 1210°C for 6h.

The Effect of the Polyamide Reinforcement on Mechanical Properties of Fluorocarbon Rubbers Exposed in Aggressive Environment

2013 ◽  
Vol 586 ◽  
pp. 230-233
Author(s):  
Barbara Romelczyk ◽  
Tomasz Brynk ◽  
Magdalena Jurczyk-Kowalska ◽  
Zbigniew Pakiela
Keyword(s):  
Mechanical Properties ◽  
Mobile Robots ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Aggressive Environment ◽  
Before And After ◽  
Proper Material ◽  
Surface Changes

The aim of presented study was to select a proper material for caterpillar application in mobile robots. The fluorocarbon rubbers were chosen for investigation. The samples hardness of 40 and 50 Sh⁰A either without or with polyamide reinforcement were prepared. The uniaxial tensile tests on mini-samples were carried out. The tests were performed on virgin samples as well as on previously exposed for one hour in aggressive liquids. The changes of the surface before and after the exposition were observed via SEM. The relation between the surface changes and the mechanical properties were described

Characterization of PLA/TPU composite filaments manufactured for 3D printing with FDM

2021 ◽  
pp. 089270572110625
Author(s):  
Ajay Jayswal ◽  
Sabit Adanur
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Thermoplastic Polyurethane ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Uniaxial Tensile ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
3D Printed

Polylactic acid (PLA) and thermoplastic polyurethane (TPU) were mixed in different proportions and extruded through twin-screw and single-screw extruders to obtain composite filaments to be used for 3D printing with fused deposition modeling (FDM) method. The properties of the filaments were characterized using uniaxial tensile tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), rheology, polarized optical microscope (POM), and scanning electron microscope (SEM). 3D printed samples from composite filaments were tested using dynamic mechanical analysis (DMA). It was found that the tensile strength and modulus of the filaments decrease while elongation at break increases with the increasing TPU content in the composite. The analysis also showed a partial miscibility of the polymer constituents in the solution of composite filaments. Finally, a flexible structure, plain weave fabric, was designed and 3D printed using the composite filaments developed which proved that the filaments are well suited for 3D printing.

3-Dimensional Microstructure Investigation of High Temperature Corrosion of Boiler Tube Material

2021 ◽  
Vol 889 ◽  
pp. 147-152
Author(s):  
Ariyana Dwiputra Nugraha ◽  
Rasgianti
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Chemical Elements ◽  
Hardness Test ◽  
Local Heat ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Visual Observation ◽  
High Temperature Corrosion ◽  
3 Dimensional

The material of the tubes has suffered localized overheating and corrosion, probably as a result of local heat flux impingement phenomenon, combined with high temperature corrosion. Boiler tubes that experienced failure indications were tubes material SA 213 T22 with the dominant alloy elements is Cr. Materials with these specifications are which should be resistant to corrosion, so it is necessary to carry out laboratory testing to answer suspected indications of failure. The methodology of analysis and identification carried out is by observing the microstructure in 3 dimensions supported by other mechanical tests, namely visual observation, hardness testing, chemical composition testing using SEM and EDAX and testing the chemical composition of the material using a spectrum analyzer. Observation using an optical microscope shows that the microstructure condition of the tube is ferritic and the results of 3D metallography observations show that the tube has undergone micro crack with a measured depth of 1853,28 μm. After the metallography testing is carried out, the hardness test is carried out with the hardness vickers (HV) unit and the minimum hardness is 149 HV and the maximum hardness is 177 HV. Testing of the chemical composition of the deposit showed that there were chemical elements found in seawater that trigger corrosion such as sodium and chlorine which enter the water vapor system. The results showed that the tube had pitting corrosion, which was indicated by the presence of microcrack at the grain boundaries and an oxide deposit had been formed which would cause an overheating phenomenon and deterioration.

Mechanical properties of a 20 vol % SiC whisker-reinforced, yttria-stabilized, tetragonal zirconia composite at elevated temperatures

1995 ◽  
Vol 10 (1) ◽  
pp. 113-118 ◽  
Author(s):  
S.E. Dougherty ◽  
T.G. Nieh ◽  
J. Wadsworth ◽  
Y. Akimune
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Tetragonal Zirconia ◽  
Tensile Tests ◽  
Engineering Properties ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Properties ◽  
Before And After

The high-temperature deformation behavior of a SiC whisker-reinforced, yttria-stabilized, tetragonal zirconia polycrystalline composite containing 20 vol % SiC whiskers (SiC/Y-TZP) has been investigated. Tensile tests were performed in vacuum at temperatures from 1450 °C to 1650 °C and at strain rates from 10−3 to 10−5 s−1. The material exhibits useful high-temperature engineering properties (e.g., ∼100 MPa and 16% elongation at T = 1550 °C and at a strain rate of ∼10−4 s−1). The stress exponent was determined to be n ≍ 2. Scanning electron microscopy was used to characterize the grain size and morphology of the composites, both before and after deformation. The grain size in the composite was initially fine, but coarsened at the test temperatures; both dynamic and static grain growth were observed. The morphology of ceramic reinforcements appears to affect strongly the plastic deformation properties of Y-TZP. A comparison is made between the properties of monolithic Y-TZP, 20 wt. % Al2O3 particulate-reinforced Y-TZP (Al2O3/Y-TZP), and SiC/Y-TZP composites.

Superplasticity in CP-Titanium Alloys

2007 ◽  
Vol 551-552 ◽  
pp. 373-378 ◽  
Author(s):  
X.J. Zhu ◽  
Ming Jen Tan ◽  
K.M. Liew
Keyword(s):  
High Temperature ◽  
Grain Growth ◽  
Initial Strain Rate ◽  
Tensile Tests ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Uniaxial Tensile ◽  
Step Method ◽  
Commercially Pure ◽  
Effects Of Temperature

In this work, studies were carried out to investigate the superplasticity of a commercially pure (CP) titanium alloy during high temperature deformation. Uniaxial tensile tests were carried out at 600, 750 and 800°C with an initial strain rate from 10-1s-1 to 10-4s-1. It was found that the alloy do not show good superplasticity due fast grain growth at high temperature and cavity. The effects of temperature on the grain growth and cavity phenomena as well as the dynamic recrystallization of the alloy were studied and a ‘two-step-method’ was introduced to increase the superplasticity of the alloy.

scholarly journals Anomalous Thermal Response of Graphene Kirigami Induced by Tailored Shape to Uniaxial Tensile Strain: A Molecular Dynamics Study

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 126 ◽  
Author(s):  
Hui Li ◽  
Gao Cheng ◽  
Yongjian Liu ◽  
Dan Zhong
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Heat Flux ◽  
Cross Section ◽  
Structural Deformation ◽  
Uniaxial Tensile ◽  
Mechanical And Thermal Properties ◽  
Atomic Lattice ◽  
Cross Section Area ◽  
Section Area

The mechanical and thermal properties of graphene kirigami are strongly dependent on the tailoring structures. Here, thermal conductivity of three typical graphene kirigami structures, including square kirigami graphene, reentrant hexagonal honeycomb structure, and quadrilateral star structure under uniaxial strain are explored using molecular dynamics simulations. We find that the structural deformation of graphene kirigami is sensitive to its tailoring geometry. It influences thermal conductivity of graphene by changing heat flux scattering, heat path, and cross-section area. It is found that the factor of cross-section area can lead to four times difference of thermal conductivity in the large deformation system. Our results are elucidated based on analysis of micro-heat flux, geometry deformation, and atomic lattice deformation. These insights enable us to design of more efficient thermal management devices with elaborated graphene kirigami materials.

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