Isothermal Mechanical Durability of Three Selected PB-Free Solders: Sn3.9Ag0.6Cu, Sn3.5Ag, and Sn0.7Cu

2005 ◽  
Vol 127 (4) ◽  
pp. 512-522 ◽  
Author(s):  
Qian Zhang ◽  
Abhijit Dasgupta ◽  
Peter Haswell
Keyword(s):  
Strain Rate ◽  
Room Temperature ◽  
Strain Range ◽  
Inelastic Strain ◽  
Total Strain Range ◽  
Homologous Temperature ◽  
Test Conditions ◽  
Mechanical Durability ◽  
Virtual Qualification ◽  
The Eu

This study is motivated by the urgent need in the electronics industry for mechanical properties and durability of Pb-free solders because the use of Pb will be banned in the EU by July 1, 2006. The isothermal mechanical durability of three NEMI recommended Pb-free solders, 95.5Sn-3.9Ag-0.6Cu, 96.5Sn-3.5Ag, and 99.3Sn-0.7Cu, is tested on the thermo-mechanical-microscale (TMM) setup under two test conditions: room temperature and relatively high strain rate, and high temperature and low strain rate. The test data are presented in a power law relationship between three selected damage metrics (total strain range, inelastic strain range, and cyclic work density) to 50% load drop. The obtained mechanical durability models of three Pb-free solders are compared with those of the eutectic 63Sn-37Pb solder at the two selected test conditions and at the same homologous temperature of 0.75. The results of this study can be used for virtual qualification of Pb-free electronics during design and development of electronics under mechanical loading.

Cyclic Mechanical Durability of Sn3.0Ag0.5Cu Pb-Free Solder Alloy

2005 ◽  
Author(s):  
Gayatri Cuddalorepatta ◽  
Abhijit Dasgupta
Keyword(s):  
Room Temperature ◽  
Strain Range ◽  
Cyclic Strain ◽  
Inelastic Strain ◽  
Mechanical Tests ◽  
Test System ◽  
Snagcu Solder ◽  
Mechanical Durability ◽  
Free Solder

The isothermal mechanical durability properties of a hypoeutectic, Sn3.0Ag0.5Cu solder are presented and compared to that of near-eutectic Sn3.9Ag0.6Cu and of baseline eutectic Sn37Pb solder. Cyclic mechanical tests are performed at room temperature at various load levels, using a custom-built thermo-mechanical-microscale (TMM) test system. Both the SnAgCu solders are found to outperform the baseline Sn37Pb, with near-eutectic Sn3.9Ag0.6Cu having the best durability. These trends are found to be in agreement with similar results available in the literature for thermal cycling durability. Fatigue results are presented in terms of both cyclic strain range and cyclic work dissipation. The effect of microstructural coarsening resulting from long-term aging at room temperature is investigated by conducting similar tests at room temperature, on the aged samples. The durability of the hypoeutectic SnAgCu solder reduced on aging, with the drop being more significant for damage curves based on cyclic work dissipation, than on cyclic inelastic strain range.

Creep and High-Temperature Isothermal Fatigue of Pb-Free Solders

2003 ◽  
Author(s):  
Qian Zhang ◽  
Abhijit Dasgupta ◽  
Peter Haswell
Keyword(s):  
High Temperature ◽  
Strain Range ◽  
Inelastic Strain ◽  
Propagation Rate ◽  
Mechanical Tests ◽  
Test System ◽  
Load Drop ◽  
Homologous Temperature ◽  
Free Solder ◽  
Sn37pb Solder

The creep resistance of Sn3.9Ag0.6Cu Pb-free solder alloy is compared to that of the baseline eutectic Sn37Pb solder at comparable homologous temperatures. Sn3.9Ag0.6Cu is significantly more creep-resistant than Sn37Pb solder. The isothermal cyclic mechanical durability of Sn3.5Ag and Sn3.9Ag0.6Cu Pb-free solder alloys are presented and compared to that of the baseline eutectic Sn37Pb solder at comparable homologous temperature. Cyclic mechanical tests are performed at high temperature at various strain-rates and load levels, using a thermo-mechanical-microstructural (TMM) test system developed by the authors. The data is analyzed using standard power-law durability models based on 50% load drop, using cyclic work and cyclic inelastic strain range. The durability curve of Sn3.9Ag0.6Cu Pb-free solder is found to have the largest slope, followed by the Sn3.5Ag solder and finally the baseline Sn37Pb eutectic solder, under the test conditions investigated. At a homologous temperature of 0.75, Sn3.9Ag0.6Cu shows the best durability, while Sn3.5Ag and Sn37Pb have very similar durability performance according to damage relations based on either work or inelastic strain range. The damage propagation rate is also estimated for all three solders, based on the load drop rate, and plotted vs. cyclic work and cyclic inelastic strain range.

scholarly journals The LCF Behavior of Several Solid Solution Strengthened Alloys Used in Gas Turbine Engines

1990 ◽  
Author(s):  
S. K. Srivastava ◽  
D. L. Klarstrom
Keyword(s):  
Low Cycle Fatigue ◽  
Fatigue Crack Initiation ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Alloy 617 ◽  
Total Strain Range ◽  
Test Conditions ◽  
Fatigue Characteristics

LCF tests were performed on production plate (16mm thick) materials of HAYNES® alloy No. 230, HASTELLOY® alloy X and INCONEL® alloy 617. The tests were conducted in air at 760, 871 and 982°C under the fully reversed strain controlled mode on materials in the annealed condition. The results showed that 230™ alloy possesses the best low cycle fatigue characteristics followed by alloy X and alloy 617 under all test conditions. The paper presents total strain range-life data, cyclic hardening/softening, and metallographic observations on selected failed samples. It is shown that oxidation plays a key role in fatigue-crack initiation in alloy 617.

A Procedure for Low Cycle Fatigue Life Prediction for Various Temperatures and Strain Rates

1990 ◽  
Vol 112 (4) ◽  
pp. 422-428 ◽  
Author(s):  
Ange Zhang ◽  
T. Bui-Quoc ◽  
R. Gomuc
Keyword(s):  
Fatigue Life ◽  
Strain Rate ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Low Frequency ◽  
Strain Range ◽  
Strain Rates ◽  
Total Strain Range ◽  
Wide Range ◽  
Experimental Values

This paper describes a procedure that permits the calculation of the fatigue life over a wide range of temperatures and strain rates. The isothermal fatigue life is expressed in terms of the total strain range by an equation previously obtained from a continuous damage concept. Additional new terms are introduced to take into account the effect of the temperature and of the strain rate. For a given material, a multiple regression analysis is carried out using some experimental results in order to evaluate the material constants involved. Once these constants are known, the life prediction can be made for other specified values of temperature and strain rate. The approach is applied to available data obtained from several stainless steels (AISI 304, 316, 348, and some SUS materials) under several combinations of temperatures and strain rates. The deviation of the calculated lives from the experimental values is reasonably acceptable. The extension of the proposed procedure to cases of cycling with a very low frequency, usually involving hold times, is examined and discussed.

Low Cycle Fatigue of Alloy 617 at 850 °C and 950 °C

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
J. K. Wright ◽  
L. J. Carroll ◽  
J. A. Simpson ◽  
R. N. Wright
Keyword(s):  
Strain Rate ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Solute Drag ◽  
Cycle Fatigue ◽  
Alloy 617 ◽  
Total Strain Range ◽  
Cycles To Failure

The low cycle fatigue behavior of Alloy 617 has been evaluated at 850 °C and 950 °C, the temperature range of particular interest for the intermediate heat exchanger on a proposed high-temperature gas-cooled nuclear reactor. Cycles to failure were measured as a function of total strain range and varying strain rate. Results of the current experiments compare well with previous work reported in the literature for a similar range of temperatures and strain rate. The combined data demonstrate a Coffin–Manson relationship, although the slope of the Coffin–Manson fit is close to −1 rather than the typically reported value of −0.5. At 850 °C and a strain rate of 10−3 /s Alloy 617 deforms by a plastic flow mechanism in low cycle fatigue and exhibits some cyclic hardening. At 950 °C for strain rates of 10−3–10−5 /s, Alloy 617 deforms by a solute drag creep mechanism during low cycle fatigue and does not show significant cyclic hardening or softening. At this temperature the strain rate has little influence on the cycles to failure for the strain ranges tested.

An experimental linear cumulative-damage law

1970 ◽  
Vol 5 (3) ◽  
pp. 177-184 ◽  
Author(s):  
K J Miller
Keyword(s):  
Strain Rate ◽  
Room Temperature ◽  
Constant Strain Rate ◽  
Strain Range ◽  
Cumulative Damage ◽  
Damage Law ◽  
Load Sequence ◽  
Number Of Cycles ◽  
Definition Of ◽  
Cycles To Failure

An hypothesis of cumulative damage is presented that may be expressed mathematically as Σn÷Nf = constant where n is the number of cycles performed at a constant strain range and strain rate and Nf is the number of cycles to failure at the same strain range and strain rate. An initial experimental investigation at room temperature shows that, under constant strain-rate conditions, the load-sequence effect is removed, but the value of the constant is dependent on the definition of failure. If failure is defined as complete rupture the summation term is less than unity whatever the sequence of loading. Should failure be defined as the termination of the steady-state period, that is at the point of crack growth instability, then the summation term is greater than unity. This latter definition therefore leads to a linear law of cumulative damage that gives a doubly cautious prediction of life that is of obvious advantage to engineers.

Tensile and Fatigue Properties of Miniature Size Specimens of Sn-5Sb Lead-Free Solder

2016 ◽  
Vol 879 ◽  
pp. 2377-2382 ◽  
Author(s):  
Kyosuke Kobayashi ◽  
Ikuo Shohji ◽  
Hiroaki Hokazono
Keyword(s):  
Fatigue Life ◽  
Strain Rate ◽  
Phase Boundary ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Total Strain ◽  
Effect Of Temperature ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Total Strain Range

Tensile and low cycle fatigue properties of Sn-5Sb (mass%) solder were investigated with miniature size tensile specimens. The effect of temperature and strain rate on tensile properties and the effect of temperature on low cycle fatigue properties were examined. Tensile strength increases with increasing strain rate regardless of temperature investigated. For elongation, the effect of temperature on it is negligible although it slightly increases with increasing strain rate. The low cycle fatigue life of Sn-5Sb obeys by the Manson-Coffin’s equation. The effect of temperature on the fatigue life is negligible in the temperature range from 25 oC to 150 oC. In the low cycle fatigue test with a high total strain range of 4%, cracking at phase boundary mainly occurs regardless of temperature investigated. In the case of a low total strain range of 0.4%, ductile fracture mainly occurs, and cracking at phase boundary with generation of grooves also occurs at high temperature.

scholarly journals Characterization of Austenitic Stainless Steels with Regard to Environmentally Assisted Fatigue in Simulated Light Water Reactor Conditions

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 307
Author(s):  
Matthias Bruchhausen ◽  
Gintautas Dundulis ◽  
Alec McLennan ◽  
Sergio Arrieta ◽  
Tim Austin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Fatigue Life ◽  
Elevated Temperature ◽  
Strain Rate ◽  
Power Plants ◽  
Research Effort ◽  
Hold Time ◽  
Strain Range ◽  
Austenitic Steels ◽  
Mean Strain

A substantial amount of research effort has been applied to the field of environmentally assisted fatigue (EAF) due to the requirement to account for the EAF behaviour of metals for existing and new build nuclear power plants. We present the results of the European project INcreasing Safety in NPPs by Covering Gaps in Environmental Fatigue Assessment (INCEFA-PLUS), during which the sensitivities of strain range, environment, surface roughness, mean strain and hold times, as well as their interactions on the fatigue life of austenitic steels has been characterized. The project included a test campaign, during which more than 250 fatigue tests were performed. The tests did not reveal a significant effect of mean strain or hold time on fatigue life. An empirical model describing the fatigue life as a function of strain rate, environment and surface roughness is developed. There is evidence for statistically significant interaction effects between surface roughness and the environment, as well as between surface roughness and strain range. However, their impact on fatigue life is so small that they are not practically relevant and can in most cases be neglected. Reducing the environmental impact on fatigue life by modifying the temperature or strain rate leads to an increase of the fatigue life in agreement with predictions based on NUREG/CR-6909. A limited sub-programme on the sensitivity of hold times at elevated temperature at zero force conditions and at elevated temperature did not show the beneficial effect on fatigue life found in another study.

scholarly journals Foldable and washable textile-based OLEDs with a multi-functional near-room-temperature encapsulation layer for smart e-textiles

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
So Yeong Jeong ◽  
Hye Rin Shim ◽  
Yunha Na ◽  
Ki Suk Kang ◽  
Yongmin Jeon ◽  
...  
Keyword(s):  
Room Temperature ◽  
Wearable Electronics ◽  
Ambient Conditions ◽  
Light Emitting ◽  
Stable Operating ◽  
Mechanical Durability ◽  
Potential Applications ◽  
Wearable Electronic ◽  
Data Signal ◽  
Wearable Electronic Devices

AbstractWearable electronic devices are being developed because of their wide potential applications and user convenience. Among them, wearable organic light emitting diodes (OLEDs) play an important role in visualizing the data signal processed in wearable electronics to humans. In this study, textile-based OLEDs were fabricated and their practical utility was demonstrated. The textile-based OLEDs exhibited a stable operating lifetime under ambient conditions, enough mechanical durability to endure the deformation by the movement of humans, and washability for maintaining its optoelectronic properties even in water condition such as rain, sweat, or washing. In this study, the main technology used to realize this textile-based OLED was multi-functional near-room-temperature encapsulation. The outstanding impermeability of TiO2 film deposited at near-room-temperature was demonstrated. The internal residual stress in the encapsulation layer was controlled, and the device was capped by highly cross-linked hydrophobic polymer film, providing a highly impermeable, mechanically flexible, and waterproof encapsulation.

The effect of strain rates on tensile deformation of ultrafine-grained copper

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744014
Author(s):  
M. Li ◽  
Q. W. Jiang
Keyword(s):  
Strain Rate ◽  
Deformation Behavior ◽  
Room Temperature ◽  
Tensile Deformation ◽  
Strain Rates ◽  
Roll Bonding ◽  
Fracture Elongation ◽  
Tensile Deformation Behavior ◽  
Ultrafine Grained ◽  
Flow Stress Level

Tensile deformation behavior of ultrafine-grained (UFG) copper processed by accumulative roll-bonding (ARB) was studied under different strain rates at room temperature. It was found that the UFG copper under the strain rate of 10[Formula: see text] s[Formula: see text] led to a higher strength (higher flow stress level), flow stability (higher stress hardening rate) and fracture elongation. In the fracture surface of the sample appeared a large number of cleavage steps under the strain rate of 10[Formula: see text] s[Formula: see text], indicating a typical brittle fracture mode. When the strain rate is 10[Formula: see text] or 10[Formula: see text] s[Formula: see text], a great amount of dimples with few cleavage steps were observed, showing a transition from brittle to plastic deformation with increasing strain rate.

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