Effect of Load-Mix on Fatigue Crack Growth in 63Sn-37Pb Solder Joints

1997 ◽  
Vol 119 (2) ◽  
pp. 114-118 ◽  
Author(s):  
D. Yao ◽  
J. K. Shang
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Load Ratio ◽  
Strain Energy Release ◽  
Fatigue Crack Growth Resistance ◽  
Sinusoidal Waveform ◽  
Energy Release Rates ◽  
Strain Energy Release Rates ◽  
Crack Growth Rates

Fatigue crack growth at the interface between Sn-Pb solder and Cu was examined under various mixed-mode conditions. The load-mix, in terms of the ratio of Mode-II to Mode-I stress intensities, was systematically changed by varying the thickness ratio of Cu layers in the flexural-peel specimens made from Sn-Pb/Cu joints. Fatigue crack growth experiments were conducted using a sinusoidal waveform at a frequency of 5 Hz and a load-ratio of zero. Fatigue crack growth rates were measured as a function of the total strain energy release rates for a given load-mix. Fatigue crack growth resistance was found to increase with the load-mix, with the effect of the load-mix being more pronounced in the near-threshold regime. The effect of the load-mix on fatigue crack growth is shown to result from shear-enhanced frictional sliding of fatigue crack surfaces.

Three Stages of Fatigue Crack Growth in GFRP Composite Laminates

2000 ◽  
Vol 123 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Jie Tong
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Energy Release ◽  
Crack Growth ◽  
Strain Energy ◽  
Strain Energy Release ◽  
Release Rates ◽  
Energy Release Rates ◽  
Three Stages ◽  
Strain Energy Release Rates

Multiple fatigue crack growth behavior has been studied in model transparent GFRP laminates. Detailed experimental observations have been made on the growth of individual fatigue cracks and on the evolution of cracks in off-axis layers in 0/90/±45S and ±45/90S laminates. Three stages of fatigue crack growth in the laminates have been identified: initiation, steady-state crack growth (SSCG), crack interaction and saturation. The results show that SSCG rate is essentially constant under constant load, independent of crack length and crack spacing. Finite element models have been developed and used to calculate the strain energy release rates associated with the off-axis matrix cracking. A correlation has been achieved between fatigue crack growth rates in off-axis layers and the total strain energy release rates.

scholarly journals Identification of Relationships between Heat Treatment and Fatigue Crack Growth of αβ Titanium Alloys

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 512 ◽  
Author(s):  
Vincent Renon ◽  
Gilbert Henaff ◽  
Céline Larignon ◽  
Simon Perusin ◽  
Patrick Villechaise
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Titanium Alloys ◽  
Crack Growth ◽  
High Performance ◽  
Shielding Effect ◽  
Characteristic Parameters ◽  
Fatigue Crack Growth Resistance ◽  
Fully Lamellar ◽  
Crack Growth Rates

This study deals with the influence of microstructure on the fatigue crack growth resistance of αβ titanium alloys: Ti-6Al-4V ELI (Extra Low Interstitial) that may compete with the conventional Ti-6Al-4V alloy in the manufacture of high performance aircraft. Six different microstructures have been considered: the as-received bimodal microstructures and five distinct fully lamellar microstructures. The characteristic parameters of these microstructures were determined and crack growth tests were performed with crack closure measurements in order to evaluate the shielding effect induced by closure. A comparison of crack growth rates, fracture surfaces, and crack path was carried out for the different microstructures. The results outline a transition between two propagation regimes from a microstructure-sensitive to microstructure-insensitive propagation.

Measurement of Fatigue Crack Growth Rates for Steels in Hydrogen Storage

2009 ◽  
Author(s):  
Yoru Wada ◽  
Kouichi Takasawa ◽  
Ryoji Ishigaki ◽  
Yasuhiko Tanaka ◽  
Tadao Iwadate
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Crack Depth ◽  
Load Ratio ◽  
Gaseous Hydrogen ◽  
Test Machine ◽  
Critical Crack ◽  
Crack Growth Rates

Fatigue crack growth rates (da/dN) in up to 90MPa high-pressure gaseous hydrogen environments of quenched and tempered low alloy Cr-Mo steel: JIS-SCM435 with ultimate tensile strength level of 950MPa were measured utilizing a cycle, ranging from 0.3sec from 1000sec long with a road ratio R = 0.1. The longer cycle time tests (15sec to 1000sec per cycle) were conducted utilizing internal pressure test apparatus by utilizing cylinder (= CY) specimens, while shorter cycle (0.3sec to 25sec per cycle) tests were performed utilizing fatigue test machine using compact tension (= C(T)) specimens. Crack depth of CY specimens were measured by Time Of Flight Diffraction (TOFD) technique and the crack length of C(T) specimens were measured by compliance technique. Both C(T) and CY specimen showed accelerated sub-critical crack growth in gaseous hydrogen compared that in air or inert gas atmosphere. The effect of load ratio was also evaluated.

Fatigue Crack Growth in a Precipitation-Hardened Martensitic Stainless Steel: Influence of Ageing, Temperature and Loading History

2014 ◽  
Vol 891-892 ◽  
pp. 961-966
Author(s):  
Loic Dimithe Aboumou ◽  
Gilbert Hénaff ◽  
Mandana Arzaghi ◽  
Sylvie Pommier
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Room Temperature ◽  
Martensitic Stainless Steel ◽  
Load Ratio ◽  
Fatigue Crack Growth Resistance ◽  
Variable Amplitude

The 15-5PH (precipitation-hardened) martensitic stainless steel is prone to embrittlement following ageing during service at temperatures between 300°C and 350°C. This results in an increase in strength and a decrease in elongation and fracture toughness. However little information is available on the consequences of long term ageing on fatigue crack growth resistance. In the present study this issue is precisely addressed at room temperature and 300°C, with different load ratio under constant amplitude loading and under variable amplitude loading.At room temperature, the results indicate a marginal effect of the load ratio, regardless of ageing conditions and temperature. While the Paris regime is not affected by ageing, a significant drop in the critical stress intensity value before unstable fracture is observed, reflecting a decrease in fracture toughness of the material with ageing. At 300°C, the FCGRs are higher than at room temperature for all ageing conditions. Variable amplitude loading tests carried out on differently-aged materials showed the same retardation effect.

Improvement of Fatigue Crack Growth Resistance by Serrated Grain Boundary at High Temperature

1991 ◽  
Vol 113 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Hiroshi lizuka ◽  
Manabu Tanaka ◽  
Fumio Ashihara
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Crack Growth ◽  
Growth Rates ◽  
Fatigue Cracks ◽  
Crack Growth Resistance ◽  
Fatigue Crack Growth Resistance ◽  
Crack Growth Rates

Effects of serrated grain boundaries on the improvement of fatigue-crack growth resistance were investigated using austenitic 21Cr-4Ni-9Mn heat-resisting steel at 973K in air. Grain boundaries were serrated by grain-boundary reaction precipitates. The crack-growth rates were considerably decreased in the specimens with the serrated grain boundaries. The fatigue cracks were largely deflected by the serrated grain boundaries, and brittle intergranular fracture was retarded. The improvement of the crack-growth resistance was obtained especially under the conditions of low crack-growth rates of less than 30 μm/cycle. The widths and the heights of the deflected portions of the cracks were in the range from about a few μm to 30 μm.

Influence of Plastic Prestrain on the Fatigue Crack Growth Resistance (da/dN vs. ΔK) of ASTM A36 Structural Steel

2015 ◽  
Author(s):  
Gustavo Henrique B. Donato ◽  
Fábio Gonçalves Cavalcante
Keyword(s):  
Mechanical Properties ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Fatigue Cracks ◽  
Pressure Vessels ◽  
Engineering Structures ◽  
Fatigue Crack Growth Resistance ◽  
Crack Growth Rates

High responsibility components operating under cyclic loading can have their resistance against initiation and growth of fatigue cracks highly influenced by previous thermomechanical processing. Within the interest of the present work, different manufacturing processes and installation techniques incorporate cold plastic straining to engineering structures; two typical examples on the oil and gas fields are: i) the offshore pipelines installation method called reeling; ii) the fabrication of pipes using the UOE method and pressure vessels through calendering. Within this scenario, this work investigates the effects of plastic prestrain on the fatigue crack growth rates (da/dN vs. ΔK) of a hot-rolled ASTM A36 steel. Different from previous results from the literature, in which prestrains were applied directly to machined samples, in this work uniform prestraining was imposed to steel strips (1/2” thick) and specimens were then extracted to avoid (or minimize) residual stress effects. Prestrain levels were around 4, 8 and 14% and C(T) specimens were machined from original and prestrained materials according to ASTM E647 standard. Fatigue crack growth tests were carried out under load control in an MTS 810 (250 kN) equipment using R = 0.1. Results revealed that plastic prestraining considerably reduced crack growth rates for the studied material, which was expected based on the literature and hardening behavior of the studied material. However, results also revealed two interesting trends: i) the larger is the imposed prestrain, the greater is the growth rate reduction in a nonlinear asymptotic relationship; ii) the larger is imposed ΔK, the more pronounced is the effect of prestraining. Crack closure effects were also investigated, but revealed no influence on the obtained mechanical properties. Consequently, results could be critically discussed based on effective crack driving forces and elastic-plastic mechanical properties, in special those related to flow and hardening. The conclusions and success of the employed methods encourage further efforts to incorporate plastic prestrain effects on structural integrity assessments.

scholarly journals Effect of morphology of primary a on fatigue crack propagation resistance in a near a heat resistant Titanium alloy

2020 ◽  
Vol 321 ◽  
pp. 11030
Author(s):  
Y. Sumi ◽  
H. Takabayashi ◽  
Hangyue Y. Li ◽  
P. Bowen
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Fatigue Threshold ◽  
Fatigue Crack Growth Resistance ◽  
Crack Propagation Resistance ◽  
Heat Resistant ◽  
Paris Region ◽  
Crack Growth Rates

DAT54 is a new near a heat resistant Ti alloy developed for disk applications in the compressor part of jet engines. DTA54 with bimodal microstructure shows a good balance of fatigue strength and creep life, and performs better than Ti-6242s up to 873 K. However, the influence of microstructure on properties, especially the effect of the morphology of primary a on fatigue crack growth resistance is not understood. In this study, samples with different types of microstructure were prepared by applying different heat treatment temperatures, and the influence of microstructure on fatigue crack growth properties at ambient temperature and 823 K was investigated. Influence of environment was also investigated by testing in vacuum and in air condition. Acicular microstructure shows lower fatigue crack growth rates in Paris’ region than the bimodal microstructures at 823 K. For the bimodal structures, aspect ratio of primary a do not have apparent influence on fatigue crack growth rates in Paris’ region, whereas fatigue threshold (DKth) seems to be affected by the morphology of primary a.

scholarly journals Oxygen Impurity Effects on Hydrogen Assisted Fatigue and Fracture of X100 Pipeline Steel

2018 ◽  
Author(s):  
Joseph Ronevich ◽  
Chris San Marchi ◽  
Robert Kolasinski ◽  
Konrad Thurmer ◽  
Norm Bartelt ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Pipeline Steel ◽  
Load Ratio ◽  
Hydrogen Gas ◽  
Mixed Gas ◽  
X100 Pipeline Steel ◽  
Crack Growth Rates

Hydrogen gas accelerates fatigue crack growth and reduces fracture toughness in ferritic structural materials such as pipelines and pressure vessels. The extent to which the crack growth rates are accelerated depends upon environment, mechanical loading conditions, and material. In this work, the effects of loading conditions and environment, specifically oxygen impurities, are examined on an X100 pipeline steel in high pressure hydrogen gas. Fatigue crack growth rates were measured in a gas mixture consisting of nominally 100 ppm O2 in a balance of H2 gas to evaluate the effects of pressure and load ratio (R-ratio) on the manifestation of hydrogen-accelerated fatigue crack growth (HA-FCG). Tests were performed at 21 MPa, 2.1 MPa, and 1.4 MPa and at load ratios of 0.5 and 0.1. The onset of HA-FCG was observed to be dependent on both absolute pressure and load ratio and it will be shown that a critical combination can result in complete mitigation of HA-FCG over the stress intensity factor range (ΔK) examined. Tests were predominantly performed at 10 Hz; however, a single test was performed at 1 Hz which exhibited negligible HA-FCG compared to a test at 10 Hz which did exhibit HA-FCG. Rising load fracture toughness tests were conducted via constant displacement rates to generate J-R curves in both pure H2 and 100 ppm O2 mixed gas. At similar absolute pressures, fracture toughness was measured to be greater in the 100 ppm O2 mixed gas compared to the pure H2. Hydrogen-assisted fracture was completely alleviated at pressures below 2.1 MPa in the 100 ppm O2 mixed gas, in which fracture toughness values were consistent with tests in air.

Fatigue Crack Growth Resistance of Several Neutron Irradiated Pressure Vessel Steels and Welds

1974 ◽  
Vol 96 (4) ◽  
pp. 242-248 ◽  
Author(s):  
P. Shahinian ◽  
H. E. Watson ◽  
J. R. Hawthorne
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Growth Resistance ◽  
Stress Intensity Factor Range ◽  
Fatigue Crack Growth Resistance ◽  
Rate Versus ◽  
Pressure Vessel Steels ◽  
Crack Growth Rates ◽  
Submerged Arc

Pre and postirradiation fatigue crack growth rates in A302-B, A533-B, and A543 steel plate and in two A543 welds (submerged arc and electroslag) were determined at 550 deg F (288 deg C) in air. The fracture mechanics approach was used to analyze the experimental data. Neutron irradiation at 585 deg F (307 deg C) to 2.5 × 1019 n/cm2, > 1 MeV produced no significant effect on resistance to crack growth in A302-B steel and caused only a slight decrease in crack growth resistance of A533-B and A543 steels. Also, the resistance to crack growth of the submerged arc weld was unaffected by the irradiation, but that of the electroslag weld was substantially improved. The crack growth rate versus stress intensity factor range curve for the A302-B steel represents an upper bound for the pre and postirradiation data for the steels and welds of this study.

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