scholarly journals Deformation mechanics of sputtered copper layers during nanoindentation tests

2020 ◽  
Vol 14 (1) ◽  
pp. 6504-6513
Author(s):  
M. A. A. Afripin ◽  
N. A. Fadil ◽  
M. Nasir Tamin
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Constitutive Equation ◽  
Coating Layer ◽  
Peak Load ◽  
Load Level ◽  
Hardening Behavior ◽  
Rate Dependent ◽  
Deformation Mechanics ◽  
Coating Layers

The mechanical properties of the thin sputtered copper layer on the SiO2-coated silicon substrate is needed as part of the requirements in quantifying the reliability of the Through-Silicon Via (TSV) interconnects. In this respect, two different Cu coating layers, each from the different sputtering process, are examined. A series of nanoindentation tests are performed on the Cu coating layer samples with indenter speeds ranging from 80 to 400 nm/s, and the indentation depths of 320 nm. The properties of elastic modulus, hardness and the hardening behavior of the Cu coating layers have been quantified. Results show that the coating with higher contamination of C at 8.41 wt. % displays a significant hardening and a peak load level, as reflected in the measured nanoindentation load-displacement curves. However, insignificant effect of the applied probe displacement speeds up to 400 nm/s on the resulting properties of the coating is registered. The Johnson-Cook constitutive equation adequately describes the strain rate-dependent hardening behavior of the Cu coating layer.

The Effects of Material Strength, Stress Ratio, and Compressive Overload on the Threshold Behavior of a SAE1045 Steel

1985 ◽  
Vol 107 (1) ◽  
pp. 19-25 ◽  
Author(s):  
M. T. Yu ◽  
T. H. Topper
Keyword(s):  
Mechanical Properties ◽  
Growth Rate ◽  
Threshold Stress ◽  
Stress Ratio ◽  
Peak Load ◽  
Load Level ◽  
Material Strength ◽  
Threshold Stress Intensity ◽  
Threshold Behavior ◽  
Rate Behavior

The fatigue crack growth rate behavior of a SAE1045 steel in the as received condition and four different quenched and tempered conditions was studied as a function of stress ratio and peak compressive overload. The threshold stress intensity behavior of the quenched and tempered conditions was not sensitive to changes of monotonic mechanical properties. The threshold decreased linearly with increasing positive stress ratio and compressive peak load level. As received ferritic-pearlitic SAE1045 steel was much more sensitive to stress ratio and compressive peak load than any of the quenched and tempered conditions studied.

scholarly journals Microstructure of Joint between Stranded Wire and Substrate Welded by Ultrasonic Welding

2019 ◽  
Vol 9 (3) ◽  
pp. 534 ◽  
Author(s):  
Chihiro Iwamoto ◽  
Keisuke Yamauchi ◽  
Kazuki Motomura ◽  
Yoichi Hashimoto ◽  
Kensuke Hamada
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Coating Layer ◽  
Ultrasonic Welding ◽  
Efficient Technique ◽  
High Quality ◽  
Cu Substrate ◽  
Coating Layers ◽  
Microscopy Techniques

In order to improvement electronic and mechanical properties, welding between stranded wires and terminals is important. However, welding methods to obtain high-quality joints using stranded wires are still limited. In this report, we applied ultrasonic welding to join a Cu stranded wire to a Cu substrate. Cross-sections of the weldments were taken and observed by several microscopy techniques to elucidate the weldability and soundness of the joints. After ultrasonic welding, each wire in the stranded wire was joined together at the region where the stranded wire was joined to the substrate without any defect. Each wire was welded through the Ag coating layer, and the stranded wire and the substrate was also welded through the outermost coating layers. It was found that ultrasonic welding is an efficient technique for producing high quality joints without any defect at the interface.

Characterizing the mechanical properties of tropoelastin protein scaffolds

2013 ◽  
Vol 1569 ◽  
pp. 45-50 ◽  
Author(s):  
Audrey C. Ford ◽  
Hans Machula ◽  
Robert S. Kellar ◽  
Brent A. Nelson
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Cell Attachment ◽  
Mechanical Design ◽  
Protein Composition ◽  
Tissue Scaffolds ◽  
Surrounding Tissue ◽  
Protein Scaffolds ◽  
Initial Stiffness ◽  
Rate Dependent

ABSTRACTThis paper reports on mechanical characterization of electrospun tissue scaffolds formed from varying blends of collagen and human tropoelastin. The electrospun tropoelastin-based scaffolds have an open, porous structure conducive to cell attachment and have been shown to exhibit strong biocompatibility, but the mechanical character is not well known. Mechanical properties were tested for scaffolds consisting of 100% tropoelastin and 1:1 tropoelastin-collagen blends. The results showed that the materials exhibited a three order of magnitude change in the initial elastic modulus when tested dry vs. hydrated, with moduli of 21 MPa and 0.011 MPa respectively. Noncrosslinked and crosslinked tropoelastin scaffolds exhibited the same initial stiffness from 0 to 50% strain, and the noncrosslinked scaffolds exhibited no stiffness at strains >∼50%. The elastic modulus of a 1:1 tropoelastin-collagen blend was 50% higher than that of a pure tropoelastin scaffold. Finally, the 1:1 tropoelastin-collagen blend was five times stiffer from 0 to 50% strain when strained at five times the ASTM standard rate. By systematically varying protein composition and crosslinking, the results demonstrate how protein scaffolds might be manipulated as customized biomaterials, ensuring mechanical robustness and potentially improving biocompatibility through minimization of compliance mismatch with the surrounding tissue environment. Moreover, the demonstration of strain-rate dependent mechanical behavior has implications for mechanical design of tropoelastin-based tissue scaffolds.

scholarly journals Nanomechanical Characterization of Canine Femur Bone for Strain Rate Sensitivity in the Quasistatic Range under Dry versus Wet Conditions

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Kun-Lin Lee ◽  
Marta Baldassarri ◽  
Nikhil Gupta ◽  
Dinesh Pinisetty ◽  
Malvin N. Janal ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Strain Rate ◽  
Cross Sections ◽  
Mechanical Response ◽  
Peak Load ◽  
Rate Sensitivity ◽  
Rate Dependent ◽  
Dry Conditions ◽  
Unloading Rate

As a strain rate-dependent material, bone has a different mechanical response to various loads. Our aim was to evaluate the effect of water and different loading/unloading rates on the nanomechanical properties of canine femur cortical bone. Six cross-sections were cut from the diaphysis of six dog femurs and were nanoindented in their cortical area. Both dry and wet conditions were taken into account for three quasistatic trapezoid profiles with a maximum force of 2000 μN (holding time = 30 s) at loading/unloading rates of 10, 100, and 1000 μN/s, respectively. For each specimen,254±9(mean ± SD) indentations were performed under different loading conditions. Significant differences were found for the elastic modulus and hardness between wet and dry conditions (P<0.001). No influence of the loading/unloading rates was observed between groups except for the elastic modulus measured at 1000 μN/s rate under dry conditions (P<0.001) and for the hardness measured at a rate of 10 μN/s under wet conditions (P<0.001). Therefore, for a quasistatic test with peak load of 2000 μN held for 30 s, it is recommended to nanoindent under wet conditions at a loading/unloading rate of 100–1000 μN/s, so the reduced creep effect allows for a more accurate computation of mechanical properties.

scholarly journals Effect of PVA fiber on mechanical properties of fly ash-based geopolymer concrete

2021 ◽  
Vol 60 (1) ◽  
pp. 418-437
Author(s):  
Peng Zhang ◽  
Xu Han ◽  
Yuanxun Zheng ◽  
Jinyi Wan ◽  
David Hui
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Volume Fraction ◽  
Peak Load ◽  
Fiber Content ◽  
Bending Test ◽  
Geopolymer Concrete ◽  
Fracture Properties ◽  
Pva Fiber

Abstract The effects of polyvinyl alcohol (PVA) fiber content on mechanical and fracture properties of geopolymer concrete (GPC) were investigated in the present study. Mechanical properties include cubic compressive, prism compressive, tensile and flexural strengths, and elastic modulus. The evaluation indices in fracture properties were measured by using the three-point bending test. Geopolymer was prepared by fly ash, metakaolin, and alkali activator, which was obtained by mixing sodium hydroxide and sodium silicate solutions. The volume fractions of PVA fiber (length 12 mm and diameter 40 μm) were 0, 0.2, 0.4, 0.6, 0.8, and 1.0%. The results indicate that the effects of the PVA fiber on the cubic and prism compressive strengths and elastic modulus are similar. A tendency of first increasing and then decreasing with the increase in the PVA fiber content was observed in these properties. They all reached a maximum at 0.2% PVA fiber content. There was also a similar tendency of first increase and then decrease for tensile and flexural strengths, peak load, critical effective crack lengths, fracture toughness, and fracture energy of GPC, which were significantly improved by the PVA fiber. They reached a maximum at 0.8% PVA fiber content, except the tensile strength whose maximum was at 1.0% PVA fiber volume fraction. Considering the parameters analyzed, it seems that the 0.8% PVA fiber content provides optimal reinforcement of the mechanical properties of GPC.

Degradation Evaluation of the Gas Turbine Hot-Gas-Path Component

2005 ◽  
Vol 297-300 ◽  
pp. 2266-2271
Author(s):  
Jine Sung Jung ◽  
S.Y. Chang ◽  
Keun Bong Yoo ◽  
Gee Wook Song ◽  
Min Sung Kang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gas Turbine ◽  
Coating Layer ◽  
Interdiffusion Zone ◽  
Hot Gas ◽  
Impact Tests ◽  
Path Component ◽  
Coating Layers ◽  
Degradation Evaluation

Degradation of the gas turbine hot-gas-path components, the 1st stage blades and vanes, serviced for a period was evaluated by measuring the mechanical properties. For this, tensile and impact tests on these gas turbine parts were performed. Microstructure of the substrate and coating layers were also observed. The mechanical properties of the serviced blades were degraded by about 30% comparing with those of unused ones. In terms of the microstructure, the dissolution of the secondary g’ phase and subsequent coarsening of precipitates were observed in the substrate. And the interdiffusion zone near the coating layer was disappeared.

Measurement of mechanical properties of multilayer waterborne coatings on wood by nanoindentation

Holzforschung ◽  
2019 ◽  
Vol 73 (9) ◽  
pp. 871-877 ◽  
Author(s):  
Yan Wu ◽  
Jiamin Wu ◽  
Siqun Wang ◽  
Xinhao Feng ◽  
Hong Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Walls ◽  
Coating Layer ◽  
Intact Cell ◽  
Bonding Mechanism ◽  
Thickness Direction ◽  
Waterborne Coatings ◽  
Coating Layers ◽  
Wood Surfaces ◽  
Coating Layer Thickness

AbstractWaterborne coatings are widely used for environmental protection. However, they lead to many defects and lower the mechanical properties when applied to wood surfaces. To address this challenge, the effects of multilayer waterborne polycrylic coatings on the mechanical properties of southern pine cell walls were investigated by nanoindentation. The experimental results indicated that the coating layers significantly reduced the elastic modulus (Er) and hardness (H) values than the wood cell walls. TheErandHvalues measured along the coating layer thickness direction increased significantly as the distance of the indents to the wood surface decreased. Intact cell walls adjacent to or away from the coating layers had higherErandHvalues than partial ones. This study will also be useful in helping to understand the bonding mechanism at the interface between coatings and wood cell walls.

Cracking at the fold in double layer coated paper: the influence of latex and starch composition

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 93-99
Author(s):  
SEYYED MOHAMMAD HASHEMI NAJAFI ◽  
DOUGLAS BOUSFIELD, ◽  
MEHDI TAJVIDI
Keyword(s):  
Mechanical Properties ◽  
Double Layer ◽  
Starch Content ◽  
Single Layer ◽  
Double Layers ◽  
Coated Paper ◽  
Coated Papers ◽  
Coating Layers ◽  
Scanned Images ◽  
Packaging Paper

Cracking at the fold of publication and packaging paper grades is a serious problem that can lead to rejection of product. Recent work has revealed some basic mechanisms and the influence of various parameters on the extent of crack area, but no studies are reported using coating layers with known mechanical properties, especially for double-coated systems. In this study, coating layers with different and known mechanical properties were used to characterize crack formation during folding. The coating formulations were applied on two different basis weight papers, and the coated papers were folded. The binder systems in these formulations were different combinations of a styrene-butadiene latex and mixtures of latex and starch for two different pigment volume concentrations (PVC). Both types of papers were coated with single and double layers. The folded area was scanned with a high-resolution scanner while the samples were kept at their folded angle. The scanned images were analyzed within a constant area. The crack areas were reported for different types of papers, binder system and PVC values. As PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content at the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. No measurable cracking was observed when the top layer was formulated with a 100% latex layer.

Effect Of Elevated Temperatures On Complete Concrete Deformation Diagrams

2019 ◽  
pp. 9-14
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Elevated Temperatures ◽  
Peak Load ◽  
Relative Deformation ◽  
Deformation Characteristics ◽  
Compression Tests ◽  
Strain Behavior ◽  
Different Temperatures ◽  
Deformation Diagrams

The analysis of the previous results of the study on concrete stress-strain behavior at elevated temperatures has been carried out. Based on the analysis, the main reasons for strength retrogression and elastic modulus reduction of concrete have been identified. Despite a significant amount of research in this area, there is a large spread in experimental data received, both as a result of compression and tension. In addition, the deformation characteristics of concrete are insufficiently studied: the coefficient of transverse deformation, the limiting relative compression deformation corresponding to the peak load and the almost complete absence of studies of complete deformation diagrams at elevated temperatures. The two testing chambers provided creating the necessary temperature conditions for conducting studies under bending compression and tension have been developed. On the basis of the obtained experimental data of physical and mechanical characteristics of concrete at different temperatures under conditions of axial compression and tensile bending, conclusions about the nature of changes in strength and deformation characteristics have been drawn. Compression tests conducted following the method of concrete deformation complete curves provided obtaining diagrams not only at normal temperature, but also at elevated temperature. Based on the experimental results, dependences of changes in prism strength and elastic modulus as well as an equation for determining the relative deformation and stresses at elevated temperatures at all stages of concrete deterioration have been suggested.

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