scholarly journals Isothermal Fatigue Behavior of Sn-Pb Solder Joints

1990 ◽  
Vol 112 (2) ◽  
pp. 94-99 ◽  
Author(s):  
T. S. E. Summers ◽  
J. W. Morris
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Strain Rate ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Load Drop ◽  
Plastic Strain Range ◽  
Double Shear ◽  
Isothermal Fatigue ◽  
Fatigue Data

Isothermal fatigue data were collected for the compositions 5Sn-95Pb, 20Sn-80Pb, 40Sn-60Pb, 50Sn-50Pb and 63Sn-37Pb within the binary Sn-Pb system. All of these compositions are commercially available and include those most commonly used. Because Sn-rich solders are rarely used, they were not investigated here. The fatigue life was defined by a 30 percent load drop. The solders were tested in a double shear configuration joined to copper at 75° C. The displacement rate chosen was 0.01 mm/min, which corresponds to a strain rate of 1.5 × 10−4s−1 for our specimen configuration, over a 10 percent plastic strain range. Additionally, the microstructural changes during fatigue are presented. The various solder compositions studied exhibit strikingly different as-solidified microstructures. These differences are discussed in terms of their effect on the isothermal joint failure mechanism and joint isothermal fatigue life.

Thermomechanical Fatigue Life Prediction of 63Sn/37Pb Solder

1992 ◽  
Vol 114 (2) ◽  
pp. 145-151 ◽  
Author(s):  
Q. Guo ◽  
E. C. Cutiongco ◽  
L. M. Keer ◽  
M. E. Fine
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Life Prediction ◽  
Strain Range ◽  
Thermomechanical Fatigue ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Fatigue Life Prediction ◽  
Total Strain ◽  
Isothermal Fatigue

Isothermal and thermomechanical fatigue of 63Sn/37Pb solder is studied under total strain-controlled tests. A standard definition of failure is proposed to allow inter-laboratory comparison. Based on the suggested failure criterion, load drop per cycle, the Young’s modulus and the ratio of the maximum tensile to maximum compressive stresses remain constant, and the fatigue response of the solder is stable before failure, although cyclic softening was observed from the beginning. Experimental results of isothermal fatigue tests for a total strain range from 0.3 to 3 percent show that the log-log plot of the number of cycles to failure versus the plastic strain range has a kink at the point where the elastic strain is approximately equal to the plastic strain. In this paper, it is shown how the isothermal fatigue life of near-eutectic solder at lower strain ranges can be predicted by using the experimental data of fatigue tests at high strain ranges and early stage information of a fatigue test at the strain range in question. A thermomechanical fatigue life prediction is also given based on a dislocation pile-up model. Comparison with experimental results shows a good agreement.

Isothermal Fatigue of 63Sn-37Pb Solder

1990 ◽  
Vol 112 (2) ◽  
pp. 110-114 ◽  
Author(s):  
E. C. Cutiongco ◽  
S. Vaynman ◽  
M. E. Fine ◽  
D. A. Jeannotte
Keyword(s):  
Fatigue Life ◽  
Hold Time ◽  
Strain Range ◽  
Maximum Tensile Stress ◽  
Air Cooling ◽  
Maximum Strain ◽  
Total Strain Range ◽  
Plastic Strain Range ◽  
Isothermal Fatigue ◽  
Cycles To Failure

The effects of aging, strain range, hold time at maximum strain and temperature on the isothermal fatigue life of bulk 63Sn-37Pn solder samples over the total strain range (Δ εT) from 0.3 to 3.0 percent (tension-tension) and within the temperature range of 25° C to 100° C were studied. The cycles to failure (Nf) were defined as the number of cycles at which the ratio of the maximum tensile stress to the maximum compressive stress starts to drop appreciably. Fatigue life increases rapidly after a day or two of aging after heat treatment at 150° C for 2 hours followed by air cooling but levels off after a week. The log of fatigue life decreases linearly with increasing log of plastic strain range above Δ εT = 0.6 percent. Hold time at maximum strain dramatically decreases the cycles to failure, however, an increase of hold time more than a few minutes eventually leads to a constant Nf. Temperature variation from 25°C to 100° C was found to have little effect on the fatigue life of the solder in tests with and without hold time. Separation of Pb-rich and Sn-rich phases and cracking of the Sn-rich phases are the main modes of fracture under all conditions used. Damage is concentrated along crisscrossing shear bands oriented approximately 45 deg to the load direction.

Fatigue Properties and Microstructure of SnAgCu Bi-Based Solder Joint

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Minghong Jian ◽  
Sinan Su ◽  
Sa'd Hamasha ◽  
Mohammad M. Hamasha ◽  
Atif Alkhazali
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Solder Joint ◽  
Solder Joints ◽  
Hysteresis Loops ◽  
Strain Range ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Solder Alloys ◽  
Plastic Strain Range

Abstract The reliability of solder joints plays a critical role in electronic assemblies. SnAgCu solder alloys with doped elements such as Bi and Sb is one of the candidates for high reliability applications. However, the mechanical and fatigue properties of the actual solder joint structure have not been studied for these new alloys. In this paper, a cyclic fatigue test was conducted on individual real solder joints of different alloys, including SnAgCu, SnCu–Bi, SnAgCu–Bi, and SnAgCu–BiSb. The fatigue property of those solder joints was analyzed based on the characteristic fatigue life and stress–strain, hysteresis, loops. The results show that solder joints with both Ag and Bi content have a better fatigue resistance than the solder joints with Ag or Bi content only. The results of SnAgCu and SnCu–Bi solder alloys show similar fatigue performance. Also, the fatigue performance of SnAgCu–Bi is close to SnAgCu–BiSb in the accelerated test. But the SnAgCu–Bi alloy is estimated to have a longer characteristic life under low-stress amplitude cycling. The microstructure analysis shows a bismuth-rich phase formed around the Ag3Sn precipitates. Adding bismuth in the solder alloy can significantly improve the fatigue properties through solid solution hardenings. On another hand, the plastic strain range and work dissipation were measured from the hysteresis loops for all tests. The Morrow Energy and the Coffin–Manson models were developed from the fitted data to predict the fatigue life as a function of work dissipation and plastic strain range.

Isothermal Fatigue Behaviour of Two Nickelbase Alloys for Turbine Blades of Fighter Aircraft Engines

2013 ◽  
Author(s):  
Benudhar Sahoo ◽  
R. K. Satpathy ◽  
S. K. Panigrahi
Keyword(s):  
Plastic Strain ◽  
Cast Alloy ◽  
Fatigue Behavior ◽  
Turbine Blades ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Cyclic Softening ◽  
Plastic Strain Amplitude ◽  
Isothermal Fatigue ◽  
Nickel Base

Turbine blades of fighter class aero-engines are subjected to repeated and unsteady throttle excursions during exploitation leading to thermo-mechanical fatigue. Failures of few turbine blades have led to premature withdrawals and major accidents. Hence, there is a need to study the high temperature fatigue behavior of these alloys. This case study deals with the isothermal fatigue behavior at 900°C for two nickel base alloys which are used for manufacturing turbine blades. The materials selected for study are precipitation strengthened wrought nickel base super alloy AP 220BD of Russian origin and western origin nickel base DS cast alloy MAR-M 002. Tensile and low cycle fatigue (LCF) tests were carried out at 900°C. LCF test was carried out at three strain ranges Δεt, i.e., ±0.3%, ±0.5% and ±0.8% using a triangular waveform of frequency 0.33 Hz with the help of MTS 800 servo hydraulic fatigue testing machine. Fractography and metallography have been done on the fracture surface to study the mode of failure and changes in morphology. Both AP220BD and MAR M 002 shows initial cyclic softening followed by cyclic hardening at low strain Δεt, i.e., ±0.3%. Stabilisation of hysteresis loop takes place at strain range Δεt ±0.5% for both the alloys. At Δεt/2 = 0.8%, AP220 BD shows cyclic hardening while MAR M 002 shows cyclic softening. MAR M 002 shows higher degree of hardening compared to that of AP220BD. The reduction in LCF life with increase in strain range is exponential for wrought alloy but for DS cast alloy it is approximately linear. LCF life has been correlated with fatigue damage parameters such as Ostergren energy(σmax Δεp) and plastic strain amplitude Δεp/2. Ostergren energy for MAR-M 002 is found to be significantly less compared to that of AP220BD. The increase in plastic strain range Δεp is significant for wrought alloys. While Ostergren energy is a good indicator of fatigue damage for wrought alloy, plastic strain amplitude Δεp/2 seems to be a better indicator for DS cast alloy. Fractography reveals inter-granular failure with initiation of cracks at at grain boundary / carbides in wrought alloy. DS cast alloy shows cleavage failure with crack initiation at pore cavities in interdendritic spacing.

Strain-Life Behavior in 60/40 Solder

1989 ◽  
Vol 111 (2) ◽  
pp. 75-82 ◽  
Author(s):  
H. D. Solomon
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Simple Shear ◽  
Curve Fitting ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Load Drop ◽  
Fitting Procedure ◽  
Life Behavior

This paper describes low cycle fatigue test run at −50°C, 35°C, 125°C, and 150°C on thin 60 Sn/40 Pb solder joints, tested in simple shear. The low cycle fatigue behavior was found to be a function of the criteria used to define the fatigue life. Different drops in the hysteresis load, measured when a constant plastic strain is being applied, was used to define failure. Not only was the magnitude of the fatigue life a function of the load drop definition for failure, it was also found that the Coffin-Manson low cycle fatigue exponent was a function of this definition. The choice of dependent variable for the curve fitting procedure used to calculate the Coffin-Manson exponent is also considered.

The low Cycle Fatigue Behavior of Three advanced Nickel-Base Eutectic Composites

1981 ◽  
Vol 12 ◽  
Author(s):  
T. Ishii ◽  
D. J. Duquette ◽  
N. S. Stoloff
Keyword(s):  
Plastic Strain ◽  
Linear Relation ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Metals And Alloys ◽  
Cycle Fatigue ◽  
Plastic Strain Range ◽  
Nickel Base

AbstractThe low cycle fatigue behavior at 25°C and 825°C of three advanced nickel-base eutectics is described. Fatigue lives are shown to obey a linear relation with plastic strain range (Coffin-Manson relation) but lives are much lower than are observed for conventional metals and alloys. Cyclic hardening and softening were observed in each alloy at 25 °C; however, this behavior differs from the classical saturation behavior observed with isotropic materials.

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.

Low-Cycle Fatigue Life of Continuously Cyclic-Hardening Material

2020 ◽  
Author(s):  
Zhong Zhang ◽  
Xijia Wu
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Root Mean Square ◽  
Low Cycle Fatigue ◽  
Cyclic Hardening ◽  
Mean Square ◽  
Cycle Fatigue ◽  
Fatigue Crack Nucleation ◽  
Hardening Material ◽  
Plastic Strain Range

Abstract A general fatigue life equation is derived by modifying the Tanaka-Mura-Wu dislocation pile-up model for variable strain-amplitude fatigue processes, where the fatigue crack nucleation life is expressed in terms of the root mean square of plastic strain range. Low-cycle fatigue tests were conducted on an austenitic stainless steel. at 400°C and 600°C, the material exhibits continuously cyclic-hardening behaviour. The root mean square of plastic strain ranges is evaluated from the experimental data for each test condition at strain rates ranging from 0.0002/s to 0.02/s. The variable-amplitude Tanaka-Mura-Wu model is found to be in good agreement with the LCF data, which effectively proves Miner’s rule on the stored plastic strain energy basis.

Low-Cycle Fatigue Life of Continuously Cyclic-Hardening Material

2021 ◽  
Author(s):  
Zhong Zhang ◽  
Xijia Wu
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Root Mean Square ◽  
Low Cycle Fatigue ◽  
Cyclic Hardening ◽  
Mean Square ◽  
Cycle Fatigue ◽  
Fatigue Crack Nucleation ◽  
Hardening Material ◽  
Plastic Strain Range

Abstract A general fatigue life equation is derived by modifying the Tanaka-Mura-Wu dislocation pile-up model for variable strain-amplitude fatigue processes, where the fatigue crack nucleation life is expressed in terms of the root mean square of plastic strain range. Low-cycle fatigue tests were conducted on an austenitic stainless steel. At 400 ? and 600 ?, the material exhibits continuously cyclic-hardening behaviour. The root mean square of plastic strain ranges is evaluated from the experimental data for each test condition at strain rates ranging from 0.0002/s to 0.02/s. The variable-amplitude Tanaka-Mura-Wu model is found to be in good agreement with the LCF data, which effectively proves Miner's rule on the stored plastic strain energy basis.

Sign in / Sign up

Export Citation Format

Share Document