Low Cycle Fatigue Test of Lead Free Solders Using Small Sized Specimen

This paper investigates the fatigue results in low cycle fatigue region obtained from a miniaturized specimen having a 6mm gage length, 3mm diameter and 55mm total length. Fatigue tests were performed for two type lead-free solders using horizontal-type electrical servo hydraulic push-pull fatigue testing machine. Materials employed were Sn-3.0Ag-0.5Cu and Sn-5Sb. The results from Sn-3.0Ag-0.5Cu were compared with those obtained using a bulk specimen in a previous study. Relationship between strain range and number of cycles to failure of the small-sized specimen agreed with those of the bulk specimens. The testing techniques are applicable to Sn-5Sb following the Manson-Coffin law. These results confirm that the testing technique proposed here, using small-sized specimen, is suitable to get fruitful fatigue data for lead-free solder compounds.

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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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An Evaluation of Low-Cycle Fatigue Property for Sn-3.5Ag and Sn-0.7Cu Lead-Free Solders Using Surface Deformation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.1035 ◽

2006 ◽

Vol 326-328 ◽

pp. 1035-1038 ◽

Cited By ~ 1

Author(s):

Takehiko Takahashi ◽

Susumu Hioki ◽

Ikuo Shohji ◽

Osamu Kamiya

Keyword(s):

Fatigue Life ◽

Surface Deformation ◽

Fatigue Testing ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Fatigue Property ◽

Lead Free ◽

Cycle Fatigue ◽

Lead Free Solders ◽

The Relationship

The low-cycle fatigue behavior and the relationship between the surface features in the low-cycle fatigue testing and the fatigue life of Sn-3.5Ag and Sn-0.7Cu lead-free solders were investigated at strain rate of 0.1%/s at room temperature, 80 and 120oC. In addition, the fatigue life was estimated by using the surface deformation of the solders, and image processing. And also, it was compared with Coffin-Manson type of fatigue behavior. The fatigue life of Sn-3.5Ag solder was superior to that of Sn-0.7Cu solder at temperatures, 80 and 120oC. The fatigue life determined by surface deformation indicated a close behavior to Coffin-Manson type fatigue behavior in those solders. Therefore the low-cycle fatigue life of solders could be estimated by the surface deformation.

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Fatigue Testing of Wearable Sensing Technologies: Issues and Opportunities

Materials ◽

10.3390/ma14154070 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4070

Author(s):

Andrea Karen Persons ◽

John E. Ball ◽

Charles Freeman ◽

David M. Macias ◽

Chartrisa LaShan Simpson ◽

...

Keyword(s):

Fatigue Life ◽

Prediction Models ◽

Fatigue Testing ◽

Low Cycle Fatigue ◽

Wearable Sensors ◽

Fatigue Tests ◽

Proof Of Concept ◽

Cycle Fatigue ◽

Wearable Sensing ◽

Failure Data

Standards for the fatigue testing of wearable sensing technologies are lacking. The majority of published fatigue tests for wearable sensors are performed on proof-of-concept stretch sensors fabricated from a variety of materials. Due to their flexibility and stretchability, polymers are often used in the fabrication of wearable sensors. Other materials, including textiles, carbon nanotubes, graphene, and conductive metals or inks, may be used in conjunction with polymers to fabricate wearable sensors. Depending on the combination of the materials used, the fatigue behaviors of wearable sensors can vary. Additionally, fatigue testing methodologies for the sensors also vary, with most tests focusing only on the low-cycle fatigue (LCF) regime, and few sensors are cycled until failure or runout are achieved. Fatigue life predictions of wearable sensors are also lacking. These issues make direct comparisons of wearable sensors difficult. To facilitate direct comparisons of wearable sensors and to move proof-of-concept sensors from “bench to bedside,” fatigue testing standards should be established. Further, both high-cycle fatigue (HCF) and failure data are needed to determine the appropriateness in the use, modification, development, and validation of fatigue life prediction models and to further the understanding of how cracks initiate and propagate in wearable sensing technologies.

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Crack Propagation Behaviour of Four Types of Lead and Lead-Free Solders in Push-Pull Low Cycle Fatigue.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A ◽

10.1299/kikaia.68.88 ◽

2002 ◽

Vol 68 (665) ◽

pp. 88-95 ◽

Cited By ~ 16

Author(s):

Haruo NOSE ◽

Masao SAKANE ◽

Mitsuo YAMASHITA ◽

Kunio SHIOKAWA

Keyword(s):

Crack Propagation ◽

Low Cycle Fatigue ◽

Lead Free ◽

Cycle Fatigue ◽

Lead Free Solders

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Crack mode and life of Ti-6Al-4V under multiaxial low cycle fatigue

Frattura ed Integrità Strutturale ◽

10.3221/igf-esis.34.54 ◽

2015 ◽

Author(s):

Takamoto Itoh ◽

Masao Sakane ◽

Takahiro Morishita ◽

Hiroshi Nakamura ◽

Masahiro Takanashi

Keyword(s):

Hollow Cylinder ◽

Stress Ratio ◽

Biaxial Loading ◽

Fatigue Testing ◽

Low Cycle Fatigue ◽

Testing Machine ◽

Multiaxial Fatigue ◽

Cycle Fatigue ◽

Loading Test ◽

Failure Life

This paper studies multiaxial low cycle fatigue crack mode and failure life of Ti-6Al-4V. Stress controlled fatigue tests were carried out using a hollow cylinder specimen under multiaxial loadings of ?=0, 0.4, 0.5 and 1 of which stress ratio R=0 at room temperature. ? is a principal stress ratio and is defined as ?=sigmaII/sigmaI, where sigmaI and sigmaII are principal stresses of which absolute values take the largest and middle ones, respectively. Here, the test at ?=0 is a uniaxial loading test and that at ?=1 an equi-biaxial loading test. A testing machine employed is a newly developed multiaxial fatigue testing machine which can apply push-pull and reversed torsion loadings with inner pressure onto the hollow cylinder specimen. Based on the obtained results, this study discusses evaluation of the biaxial low cycle fatigue life and crack mode. Failure life is reduced with increasing ? induced by cyclic ratcheting. The crack mode is affected by the surface condition of cut-machining and the failure life depends on the crack mode in the multiaxial loading largely.

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