Effect of Small Amount of Ni Addition on Microstructure and Fatigue Properties of Sn-Sb-Ag Lead-Free Solder

The effect of the addition volume of Ni on the microstructures and tensile and fatigue properties of Sn-6.4Sb-3.9Ag (mass%) was investigated using micro-size specimens. The addition of Ni into Sn-6.4Sb-3.9Ag tends to increase the number of grains formed in the solidification process and produce a high-angle grain boundary. An amount of 0.1% proof stress of Sn-6.4Sb-3.9Ag decreases with an increase in the Ni addition volume at a strain rate of 2.0 × 10−1 s−1. The effect of the addition of Ni into Sn-6.4Sb-3.9Ag on tensile strength is negligible at both 25 °C and 175 °C. The elongation of Sn-6.4Sb-3.9Ag decreases with an increase in the Ni addition volume at 25 °C according to the fracture mode change from ductile chisel point fracture to shear fracture. The effect of the addition of Ni into Sn-6.4Sb-3.9Ag on the elongation is negligible at 175 °C. The low cycle fatigue test result shows that the fatigue life does not degrade even at 175 °C in all alloys investigated. The fatigue life of Sn-6.4Sb-3.9Ag-0.4Ni (mass%) is superior to those of Sn-6.4Sb-3.9Ag and Sn-6.4Sb-3.9Ag-0.03Ni (mass%) in the high cycle fatigue area. The electron back scattering diffraction (EBSD) analysis result shows that fine recrystallized grains are generated at the cracked area in Sn-6.4Sb-3.9Ag-0.4Ni in the fatigue test at 175 °C, and the crack progresses in a complex manner at the grain boundaries.

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Tensile and Fatigue Properties of Miniature Size Specimen of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge Lead-Free Solder

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.2081 ◽

2018 ◽

Vol 941 ◽

pp. 2081-2086

Author(s):

Masaki Yokoi ◽

Tatsuya Kobayashi ◽

Ikuo Shohji

Keyword(s):

Tensile Strength ◽

Fatigue Life ◽

Low Cycle Fatigue ◽

Ternary Eutectic ◽

Lead Free ◽

Fatigue Properties ◽

Lead Free Solder ◽

Cycle Fatigue ◽

Proof Stress ◽

Free Solder

Tensile and low cycle fatigue properties of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge (mass%) lead-free solder were investigated using miniature size specimens and obtained data were compared to those of Sn-3.0Ag-0.5Cu (mass%). The microstructure of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge consists of dendritic β-Sn phases and ternary eutectic phases surrounding them which are composed of β-Sn, (Cu,Ni)6Sn5 and Ag3Sn. Tensile strength and 0.1% proof stress of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge are superior to those of Sn-3.0Ag-0.5Cu at 25°C and 150°C. However, elongation of it is inferior to that of Sn-3.0Ag-0.5Cu at both temperatures. Fatigue lives of both alloys obey the Manson-Coffin equation and are analogous at 25°C. Although fatigue lives of both alloys decrease at 150°C, the fatigue life of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge is inferior to that of Sn-3.0Ag-0.5Cu. At 150°C, the crack mainly progresses at grain boundaries of recrystallized grains. Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge has several grain boundaies which can be the origin of the crack so that fatigue lives degrade at 150°C.

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Low Cycle Fatigue Behavior and Surface Feature by Image Processing of Sn-0.7Cu Lead-Free Solder

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.306-308.115 ◽

2006 ◽

Vol 306-308 ◽

pp. 115-120 ◽

Cited By ~ 1

Author(s):

Takehiko Takahashi ◽

Susumu Hioki ◽

Ikuo Shohji ◽

Osamu Kamiya

Keyword(s):

Fatigue Life ◽

Fatigue Test ◽

Surface Deformation ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Surface Feature ◽

Lead Free ◽

Lead Free Solder ◽

Cycle Fatigue ◽

Free Solder

The low-cycle fatigue behavior on Sn-0.7Cu lead-free solder as-cast and Sn-Pb eutectic solder as-cast were investigated at a strain rate 0.1%/s under various temperatures of 25, 80 and 120oC. In addition, the relationships between the surface feature in the low-cycle fatigue test and low-cycle fatigue life of those solders at 25oC were investigated by image processing. The low-cycle fatigue life of Sn-0.7Cu decreased when the temperature increased. And the fatigue life of Sn-0.7Cu was better than that of the Sn-Pb eutectic solder at the temperatures of 25 and 80oC. The low-cycle fatigue behavior on the solders investigated followed Coffin-Manson equation. The fatigue ductility coefficient of Sn-0.7Cu was found to be affected by the temperature. The surface deformation as fine meshes in the low-cycle fatigue test of Sn-0.7Cu did not appear until 10% of the fatigue life. Although it was over 10% of the fatigue life, the surface deformation that was caused by micro cracks and coalesces occurred with the increasing number of cycles. The relationships between the surface feature in the low-cycle fatigue test and the low-cycle fatigue life on Sn-0.7Cu and Sn-37Pb solders were discussed.

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Low Cycle Fatigue Properties of FGH720Li Superalloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1035.292 ◽

2021 ◽

Vol 1035 ◽

pp. 292-296

Author(s):

Zi Chao Peng ◽

Jun Ying Sheng ◽

Xu Qing Wang ◽

Yue Tang

Keyword(s):

Fatigue Life ◽

Powder Metallurgy ◽

Applied Stress ◽

Low Cycle Fatigue ◽

Influencing Factor ◽

Fatigue Tests ◽

Fatigue Properties ◽

Nickel Base Superalloy ◽

Loading Frequency ◽

Cycle Fatigue

Low cycle fatigue (LCF) properties of a powder metallurgy(PM) nickel base superalloy FGH720Li were systematically studied in this work, including smooth LCF and notched LCF tested at various temperatures and different stress. The relationship between the fatigue life and applied stress was analyzed both for smooth fatigue and notch fatigue tests. The effects of loading frequency and stress ratio on LCF behavior were also studied. As an important influencing factor of the fatigue life in powder metallurgy superalloy, the effect of inclusions on LCF life was also investigated. The results showed that the fatigue properties of FGH720Li alloy was excellent, when tested at the temperature of 450°C and applied stress of 1230MPa, the fatigue life could exceed 5×104 cycles. When tested at 650°C and 1150MPa, the average fatigue life was still beyond 2×105 cycles.

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High-Temperature Fatigue Properties of Single Crystal Superalloys in Air and Hydrogen

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1501075 ◽

2004 ◽

Vol 126 (3) ◽

pp. 590-603 ◽

Cited By ~ 19

Author(s):

N. K. Arakere

Keyword(s):

Fatigue Life ◽

Single Crystal ◽

Room Temperature ◽

Low Cycle Fatigue ◽

Turbine Blades ◽

Fatigue Properties ◽

Cycle Fatigue ◽

Fatigue Data ◽

Blade Tip ◽

Pressure Hydrogen

Hot section components in high-performance aircraft and rocket engines are increasingly being made of single crystal nickel superalloys such as PWA1480, PWA1484, CMSX-4, and Rene N-4 as these materials provide superior creep, stress rupture, melt resistance, and thermomechanical fatigue capabilities over their polycrystalline counterparts. Fatigue failures in PWA1480 single crystal nickel-base superalloy turbine blades used in the space shuttle main engine fuel turbopump are discussed. During testing many turbine blades experienced stage II noncrystallographic fatigue cracks with multiple origins at the core leading edge radius and extending down the airfoil span along the core surface. The longer cracks transitioned from stage II fatigue to crystallographic stage I fatigue propagation, on octahedral planes. An investigation of crack depths on the population of blades as a function of secondary crystallographic orientation (β) revealed that for β=45+/−15 deg tip cracks arrested after some growth or did not initiate at all. Finite element analysis of stress response at the blade tip, as a function of primary and secondary crystal orientation, revealed that there are preferential β orientations for which crack growth is minimized at the blade tip. To assess blade fatigue life and durability extensive testing of uniaxial single crystal specimens with different orientations has been tested over a wide temperature range in air and hydrogen. A detailed analysis of the experimentally determined low cycle fatigue properties for PWA1480 and SC 7-14-6 single crystal materials as a function of specimen crystallographic orientation is presented at high temperature (75°F–1800°F) in high-pressure hydrogen and air. Fatigue failure parameters are investigated for low cycle fatigue data of single crystal material based on the shear stress amplitudes on the 24 octahedral and 6 cube slip systems for FCC single crystals. The max shear stress amplitude [Δτmax] on the slip planes reduces the scatter in the low cycle fatigue data and is found to be a good fatigue damage parameter, especially at elevated temperatures. The parameter Δτmax did not characterize the room temperature low cycle fatigue data in high-pressure hydrogen well because of the noncrystallographic eutectic failure mechanism activated by hydrogen at room temperature. Fatigue life equations are developed for various temperature ranges and environmental conditions based on power-law curve fits of the failure parameter with low cycle fatigue test data. These curve fits can be used for assessing blade fatigue life.

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A Study on Strain Concentration Around V Notch in Lead Free Solder Material and the Low Cycle Fatigue Life

Volume 2: Advanced Electronics and Photonics, Packaging Materials and Processing; Advanced Electronics and Photonics: Packaging, Interconnect and Reliability; Fundamentals of Thermal and Fluid Transport in Nano, Micro, and Mini Scales ◽

10.1115/ipack2015-48136 ◽

2015 ◽

Author(s):

Takashi Kawakami ◽

Takahiro Kinoshita ◽

Hirokazu Oriyama

Keyword(s):

Fatigue Life ◽

Solder Joints ◽

Low Cycle Fatigue ◽

Lead Free ◽

Design Rule ◽

Lead Free Solder ◽

Cycle Fatigue ◽

Stress Strain ◽

Test Pieces ◽

Free Solder

Solder joints are sometimes opened under thermal cyclic loads as low cycle fatigue phenomena. The fatigue crack is usually initiated around the edge of the interface where stress and strain very severely concentrate, having stress strain singularity. In this study, Sn-3.0Ag-0.5Cu test pieces with V shape notch were supplied to low cycle fatigue tests at 100°C. And inelastic stress strain simulations, which were based on time-dependent non-unified material model, were carried out under several cyclic load levels to obtain strain distributions around the bottom of the V notch. By results of fatigue test and inelastic simulation, the depth from the bottom of the V notch, where the strain range agrees with the prediction of the fatigue life based on smooth test pieces on Coffin-Manson rule, was investigated as the mechanical design rule for lead free solder joints.

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Low-Cycle Fatigue Reliability Evaluation for Lead-Free Solders in Vehicle Electronics Devices

ASME 2007 InterPACK Conference, Volume 1 ◽

10.1115/ipack2007-33250 ◽

2007 ◽

Cited By ~ 11

Author(s):

Qiang Yu ◽

Tadahiro Shibutani ◽

Akifumi Tanaka ◽

Takahiro Koyama ◽

Masaki Shiratori

Keyword(s):

Fatigue Life ◽

Crack Propagation ◽

Low Cycle Fatigue ◽

Strain Range ◽

Reliability Evaluation ◽

Lead Free ◽

Generation Process ◽

Lead Free Solder ◽

Cycle Fatigue ◽

Free Solder

The changeover from eutectic Sn-Pb solder to lead-free solder (Sn-Ag-Cu) has been driven by environmental concerns in the last few years. In this study, in order to obtain the low-cycle fatigue characteristic of Sn-Ag-Cu lead-free solder joints, an isothermal mechanical fatigue test with a large strain range, which can clarify the crack generation process and shorten the examination time, was carried out. FEM analysis was also performed in order to evaluate the relationship between the inelastic strain range and the low-cycle fatigue life. As a result, compared with fatigue life longer than 1000 cycles, the scatter of the fatigue cycles from 100 to several hundred cycles becomes larger. So, it seems that it is necessary to carefully evaluate the low-cycle fatigue life in the reliability evaluation. Moreover, in large chip components, not only crack initiation, but also crack propagation, affects the failure life. Thus, the crack path was simulated and the failure cycle of the large chip was evaluated based on Miner’s rule, and reliability of including the fatigue crack propagation can be evaluated by the analytical approach.

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Low Cycle Fatigue Evaluation of Inconel 713C and Waspaloy

Journal of Basic Engineering ◽

10.1115/1.3650539 ◽

1965 ◽

Vol 87 (2) ◽

pp. 275-289 ◽

Cited By ~ 25

Author(s):

JoDean Morrow ◽

F. R. Tuler

Keyword(s):

Fatigue Life ◽

Plastic Strain ◽

Strain Energy ◽

Room Temperature ◽

Low Cycle Fatigue ◽

Fatigue Properties ◽

Cycle Fatigue ◽

Plastic Strain Energy ◽

Fatigue Evaluation ◽

Inconel 713C

Completely reversed axial fatigue results are reported for Waspaloy and Inconel 713C at room temperature. Fatigue strength and ductility are evaluated using power functions of the fatigue life. The exponents and coefficients of these two equations are looked upon as four fatigue properties of the material. They appear in the equations which are developed to relate cyclic stress, plastic strain, total strain, plastic strain energy per cycle, total plastic strain energy to fracture, and fatigue life. These equations and the four fatigue properties permit the evaluation of the relative fatigue resistance of various metals at different fatigue lives when subjected to strain, stress, or plastic strain energy cycling. The “best” selection of material to resist fatigue is found to depend on the type of cycling and the desired life. At room temperature, the wrought Waspaloy is found to be more fatigue resistant than the cast Inconel 713C, particularly in resisting strain or plastic strain energy cycling in the low cycle fatigue region. For longer lives the difference in fatigue resistance between the two diminishes, especially for stress cycling. It is believed that the method of fatigue evaluation used here is generally applicable to the engineering problem of material selection to resist fatigue, and should in some cases replace methods based on conventional rotating bending fatigue tests which only evaluate the fatigue strength at long lives.

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Enhancing Fatigue Properties of Nanostructured Metals and Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.29-30.117 ◽

2007 ◽

Vol 29-30 ◽

pp. 117-122 ◽

Cited By ~ 2

Author(s):

Terry C. Lowe

Keyword(s):

Fatigue Life ◽

Crack Initiation ◽

Computational Methods ◽

High Cycle Fatigue ◽

Low Cycle Fatigue ◽

Metals And Alloys ◽

Fatigue Properties ◽

Cycle Fatigue ◽

Nanostructured Metals ◽

Improve Fatigue

Recent research on the fatigue properties of nanostructured metals and alloys has shown that they generally possess superior high cycle fatigue performance due largely to improved resistance to crack initiation. However, this advantage is not consistent for all nanostructured metals, nor does it extend to low cycle fatigue. Since nanostructures are designed and controlled at the approximately the same size scale as the defects that influence crack initiation attention to preexisting nanoscale defects is critical for enhancing fatigue life. This paper builds on the state of knowledge of fatigue in nanostructured metals and proposes an approach to understand and improve fatigue life using existing experimental and computational methods for nanostructure design.

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An Evaluation of Fatigue Damage in Low-Cycle Range for Sn-3.5Ag, Sn-0.7Cu Lead-Free Solders and Sn-Pb Eutectic Solder Using Image Processing to Surface Feature

Advances in Electronic Packaging, Parts A, B, and C ◽

10.1115/ipack2005-73152 ◽

2005 ◽

Author(s):

Takehiko Takahashi ◽

Susumu Hioki ◽

Ikuo Shohji ◽

Osamu Kamiya

Keyword(s):

Image Processing ◽

Fatigue Life ◽

Fatigue Test ◽

Surface Deformation ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Lead Free ◽

Cycle Fatigue ◽

Surface Features ◽

Lead Free Solders

The low-cycle fatigue behavior of Sn-3.5mass%Ag, Sn-0.7mass%Cu lead-free solders and Sn-37mass%Pb solder were investigated at strain rate of 0.1%/s with a non-contact extensometer at room temperature (22 ± 3 °C). In addition, the relationship between the surface features in the low-cycle fatigue test and the fatigue life of those solders were investigated by image processing. The fatigue lives of Sn-3.5mass%Ag and Sn-0.7mass%Cu were better than that of Sn-37mass%Pb. The low-cycle fatigue behavior on each solder followed Coffin-Manson equation. The surface deformation in fine wrinkles was observed in the low-cycle fatigue test at each solder. The surface features for each solder were evaluated by image processing from the surface deformation. The surface features in the low-cycle fatigue test did not appear until under 10% of the fatigue life for Sn-3.5mass%Ag, until 10% of the fatigue life for Sn-0.7mass%Cu, and until 20% of the fatigue life for Sn-37mass%Pb.

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