Fatigue Lives on 60Sn/40Pb Solder Joints Made With Different Cooling Rates

1992 ◽  
Vol 114 (2) ◽  
pp. 104-108 ◽  
Author(s):  
Z. Mei ◽  
J. W. Morris
Keyword(s):  
Grain Size ◽  
Fatigue Life ◽  
Cooling Rate ◽  
Solder Joints ◽  
Phase Morphology ◽  
Air Cooling ◽  
Test Results ◽  
Cooling Rates ◽  
Isothermal Fatigue ◽  
Shear Fatigue

This paper reports the results of a study on the effect of the cooling rate during solidification on the isothermal shear-fatigue life of 60Sn/40Pb solder joints. Solder joints are made with three different initial microstructures by quenching, air-cooling, and furnace-cooling. The test results show that the quench-solidified solder joints have isothermal fatigue lives of about twice long as those of the furnace cooled solder joints tested at 20°C and 65°C with the straining rates of about 10−4 per s. These results are ascribed to the refined grain size and less lamellar phase morphology that results on increasing the cooling rate.

Fatigue Lifetimes of PBGA Solder Joints Reflowed at Different Conveyor Speeds

1999 ◽  
Vol 123 (3) ◽  
pp. 290-294 ◽  
Author(s):  
S. H. Fan ◽  
Y. C. Chan ◽  
J. K. L. Lai
Keyword(s):  
Cooling Rate ◽  
Solder Joints ◽  
Bulk Solder ◽  
Test Results ◽  
Heat Transmission ◽  
Fatigue Lifetime ◽  
Shear Fatigue ◽  
Sliding Mechanism ◽  
Plastic Ball ◽  
Plastic Ball Grid Array

The shear cycle fatigue lifetimes of plastic ball grid array (PBGA) solder joints formed using different reflow profiles are studied in this paper. The profiles were devised to have the same “heating factor” but to have different conveyor speeds. The test results show that, by increasing the conveyor speed during reflow, the shear fatigue lifetime of solder joints can be improved substantially. On the other hand, the fatigue lifetime of the test specimens decreased with increasing the cycle displacement amplitude. Heat transmission analysis shows that increasing conveyor speed increases the cooling rate during solder solidification. SEM micrographs reveal that cracks initiated at the acute point near the PCB solder pad, then propagate along the interface of the bulk solder/IMC layer. The test results are ascribed to roughing interface of the bulk solder/IMC of the solder joints that results on increasing the cooling rate. The frictional sliding mechanism is used to explain the test results.

Effect of cooling rate on the isothermal fatigue behavior of CBGA solder joints in shear

2001 ◽  
Vol 24 (1) ◽  
pp. 10-16 ◽  
Author(s):  
S.H. Fan ◽  
Y.C. Chan ◽  
C.W. Tang ◽  
J.K.L. Lai
Keyword(s):  
Cooling Rate ◽  
Solder Joints ◽  
Fatigue Behavior ◽  
Isothermal Fatigue

scholarly journals Influence of the Microstructure on the Creep Behaviour of Tin-Silver-Copper Solder

2018 ◽  
Author(s):  
Pedro E. Ribeiro ◽  
Delfim F. Soares ◽  
Maria F. Cerqueira ◽  
Senhorinha F. Teixeira ◽  
Daniel A. Barros ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Solder Joint ◽  
Cooling Rate ◽  
Printed Circuit Boards ◽  
Creep Behaviour ◽  
Creep Tests ◽  
Cooling Rates ◽  
Pcb Assembly ◽  
Solder Joint Fatigue ◽  
Tin Silver Copper

A common failure mode of electronic printed circuit boards (PCB’s) is the appearance of cold solder joints between the component and PCB, during product life. This phenomenon is related to solder joint fatigue and is attributed mainly to the mismatch of the coefficients of thermal expansion (CTE) of component-solder-PCB assembly. With today’s solder joint thickness decreasing and increasing working temperatures, among others, the stresses and strains due to temperature changes are growing, leading to limited fatigue life of the products. As fatigue life decreases with increasing plastic strain, creep occurrence should have significant impact, especially during thermal cycles and, thus, should be studied. Through the cooling phase, on the production of PCB assembly’s by the reflow technology, the hoven atmosphere temperature is adjusted in order to control the cooling rate. Narrow criteria is used so as to control the inter-metallic compounds (IMC) thickness, PCB assembly distortion and defects due to thermal shock. The cooling rate also affects solder microstructure, which has direct impact on creep behaviour and, thus, on the soldered joint reliability. In this paper, a dynamic mechanical analyser (DMA) is used to study the influence of the solder cooling rate on its creep behaviour. SAC405 samples with two distinct cooling rates were produced: inside a hoven cooling and by water quenching. Creep tests were made on three-point-bending clamp configuration, isothermally at 25 °C, 50 °C and 75 °C and under three separate levels of stress, 3, 5 and 9 MPa. The results show that creep behaviour has a noticeable cooling rate dependence. It was also noticed that creep propensity is exacerbated by the temperature at which stresses are applied, especially for the slower cooling rates. Creep mechanisms were related to the solder microstructural constituents, namely by the amount of phases ant their morphology.

Effect of Micro Structure on Fatigue Characteristics of Lead Free Solder Joints

2011 ◽  
Author(s):  
Takahiro Akutsu ◽  
Qiang Yu
Keyword(s):  
Grain Size ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Solder Joint ◽  
Crack Propagation ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Micro Structure ◽  
Free Solder

This paper presents the influence of the micro structure on the crack propagation in lead free solder joint. The author’s group have studied the Manson-Coffin’s law for lead free solder joint by using the isothermal fatigue test and FEM analytical approaches to establish the practicable evaluation of thermal fatigue life of solder joints, for example, for the Sn-Cu-Ni solder, because this solder is attracted from the aspect of the decrease of solder leach in the flow process and material cost. However, even if the same loading is given to the solder joints of BGA test piece, there was a large dispersion in the fatigue life. Even though the effect of the shape difference has been considered, the range of the dispersion could not been explained sufficiently. In the study, the fatigue crack propagation modes in the solder joints were investigated, and an internal fatigue crack mode and an interfacial fatigue crack mode were confirmed. And the tendency of a shorter on fatigue life in the interfacial fatigue mode was confirmed. To clarify the mechanism of these fatigue crack modes, the crystal grain size in the solder joints was investigated before the fatigue test and also after the test. Furthermore, the verification of the mechanism using FEM models considering the crystal grain size was carried out. First of all, each element in FEM models matching to the average crystal grain size was made. Second, the inelastic strain ranges in each FEM models were studied. As a result, it was shown that the influence of the crude density of the crystal grain to the fatigue crack progress can be evaluated. In addition, the micro structure of the solder joint of large-scale electronic devices is observed, and FEM model was made based on the observation result. As a result, it was shown that the influence of the directionality with the crystal grain to the fatigue crack progress can be evaluated.

Effect of Cooling Condition on Zr-Rich Core Formation and Grain Size in Mg Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 3920-3924
Author(s):  
Hong Hui Liu ◽  
Zhing Liang Ning ◽  
Fu Yang Cao ◽  
Zhi Jun Meng ◽  
Jian Fei Sun
Keyword(s):  
Grain Size ◽  
Cooling Rate ◽  
Cooling Condition ◽  
Mg Alloy ◽  
Core Formation ◽  
Cooling Rates ◽  
Zr Addition ◽  
Sand Mould ◽  
Zr Alloys

The effects of cooling condition on the Zr-rich core formation and grain size in Mg-Zr alloys were investigated in this study. Four moulds with various cooling rates and different Zr additions were used. The results show that when Zr addition was 1.2%, the Zr-rich cores were round and their diameters increased with decreased cooling rates. When Zr addition content was decreased to 0.7%, Zr-rich cores formed only in the sand mould with the lowest cooling rate used in this study, and the morphology changed to rosette-like. The influence of cooling rate on grain size of Mg-Zr alloys was also investigated.

Reliability Evaluation of Fatigue Life for Solder Joints in Chip Components Considering Dispersion of the Shape and the Properties

2011 ◽  
Author(s):  
Yuji Nishimura ◽  
Qiang Yu
Keyword(s):  
Fatigue Life ◽  
Material Properties ◽  
Solder Joints ◽  
Test Method ◽  
Fatigue Properties ◽  
Simulation Approach ◽  
Fiber Network ◽  
Heterogeneous Model ◽  
Isothermal Fatigue ◽  
Simulation Results

Recently, the downsizing of car components becomes a big trend for the development of car electronics, and it is becoming very difficult to achieve the reliability results target without managing controlling the dispersion of the fatigue lives. The authors proposed an isothermal fatigue test method using small size solder joints to get the fatigue properties. The Manson-Coffin’s law given by this method could improve the correspondence between the simulation results and experimental results. Based upon the Manson-Coffin’s law and Miner’s law, the authors proposed a fatigue crack propagation simulation approach. Furthermore, in order to consider the heterogeneity of PCB due to the distribution of fiber network, the authors made heterogeneous model considering the distribution of the fiber. And the authors evaluated the fatigue life of solder joints in chip components with considering dispersion of the material properties by using the heterogeneous model.

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.

Silica Additions and the Performance of PTC Thermistors

2006 ◽  
Vol 45 ◽  
pp. 2362-2370
Author(s):  
Colin Leach ◽  
M. Zubair ◽  
Robert Freer
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Cooling Rate ◽  
Microstructural Development ◽  
Electrical Behaviour ◽  
Cooling Rates ◽  
Sample Density

A series of PTC thermistors, based on BaTiO3, doped with Ca, Mn and Y, were prepared with additions of SiO2 at levels of 0, 1, 2 and 3 at. %. The effect of the SiO2 additions and cooling rate on microstructural development and bulk performance were characterised using a combination of SEM, EBSD, and R-T experiments. It was found that the addition of SiO2 increased grain size marginally, and decreased sample density by reducing the amount of grain-grain contact. The addition of SiO2 also modified the distribution of grain boundary types by systematically decreasing the proportion of low-Σ grain boundaries within the microstructure. Electrical behaviour was modified by adding SiO2 or increasing the sample cooling rates; in both cases there was an increase in ρ25 and a decrease in ρmax, with ρmax also being displaced to higher temperatures.

Microstructural Aspects of Recrystallization-Controlled Rolling in V-Ti-N Steels

1985 ◽  
Vol 43 ◽  
pp. 334-335
Author(s):  
M.G. Burke ◽  
R.M. Fix ◽  
A.J. DeArdo
Keyword(s):  
Grain Size ◽  
Cooling Rate ◽  
Steel Industry ◽  
Room Temperature ◽  
Controlled Rolling ◽  
Accelerated Cooling ◽  
Air Cooling ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Processing Treatment

Recrystallization controlled rolling (RCR) has been developed as an economically viable alternative to conventional controlled rolling, a thermomechanica1 processing treatment currently employed in the steel industry. RCR processing involves deformation below the austenite grain coarsening temperature of the steel, followed by accelerated cooling to an intermediate temperature and air cooling to room temperature. The V-Ti-N system is well-suited to RCR processing because Ti (in the form of TiN precipitates) promotes a fine reheated austenite grain size while the V in solution in the austenite will be available for subsequent precipitation in the ferrite. The precipitation potential of V-Ti steels has been shown to increase with increasing N content and cooling rate.

Effect of Cooling Rate on Microstructure of Rejuvenated Fe-Ni Based Superalloys

2020 ◽  
Vol 856 ◽  
pp. 76-84
Author(s):  
Kittawat Srimark ◽  
Panyawat Wangyao ◽  
Tanaporn Rojhirunsakool
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
High Temperature ◽  
Cooling Rate ◽  
Volume Fraction ◽  
Air Cooling ◽  
Gamma Prime ◽  
Microstructural Instability ◽  
Cooling Air

Fe-Ni based superalloys have been widely used in land-base gas turbine application. The turbine blade was in service for 50,000 h at high temperature and stresses. When subjected to long-term exposure at high temperature, the microstructure lost its best mechanical properties due to the microstructural instability. The aim of this research is to understand the effect of cooling rate on gamma (γ) grain size and gamma prime (γ’) particle size, morphology, and its volume fraction in rejuvenated Fe-Ni based superalloys. The alloys were solutionized above the γ’ solvus temperature at 1125 °C for 2 h for homogenization and cooling to room temperature at different cooling rates. The alloys were experienced with furnace cooling, air cooling, oil quenching, and water quenching. Microstructural analyses were investigated. Grain size, morphology, volume fraction of γ’ precipitates were investigated. Preliminary mechanical properties such as microhardness was conducted.

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