scholarly journals Evaluation of Fatigue Characteristics of Aluminum Alloys and Mechanical Components Using Extreme Value Statistics and C-specimens

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1915
Author(s):  
Jungsub Lee ◽  
Sang-Youn Park ◽  
Byoung-Ho Choi
Keyword(s):  
Aluminum Alloys ◽  
Fem Analysis ◽  
Extreme Value ◽  
Fatigue Tests ◽  
Extreme Value Statistics ◽  
Fatigue Properties ◽  
Chemical Compositions ◽  
Cross Sectional ◽  
Fatigue Characteristics ◽  
Mechanical Components

In this study, the fatigue characteristics of aluminum alloys and mechanical components were investigated. To evaluate the effect of forging, fatigue specimens with the same chemical compositions were prepared from billets and forged mechanical components. To evaluate the cleanliness of the aluminum alloys, the cross-sectional area of specimens was observed, and the maximum inclusion sizes were obtained using extreme value statistics. Rotary bending fatigue tests were performed, and the fracture surfaces of the specimens were analyzed. The results show that the forging process not only elevated the fatigue strength but also reduced the scatter of the fatigue life of aluminum alloys. The fatigue characteristics of C-specimens were obtained to develop finite-element method (FEM) models. With the intrinsic fatigue properties and strain–life approach, the FEM analysis results agreed well with the test results.

Thermal Fatigue Characteristics of Heat-Resisting Stainless Steel for Automotive Exhaust

2007 ◽  
Vol 539-543 ◽  
pp. 4944-4949 ◽  
Author(s):  
Tae Kwon Ha ◽  
Hwan Jin Sung
Keyword(s):  
Thermal Fatigue ◽  
Stainless Steels ◽  
Fatigue Property ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Automotive Exhaust ◽  
Load Relaxation ◽  
Temperature Ranges ◽  
Fatigue Characteristics ◽  
Efficiency And Reliability

Thermal fatigue is a complex phenomenon encountered in materials exposed to cyclically varying temperatures in the presence or absence of external load. Continually increasing working temperature and growing need for greater efficiency and reliability of automotive exhaust require immediate investigation into the thermal fatigue properties especially of high temperature stainless steels. In this study, thermal fatigue properties of 304 and 429EM stainless steels have been evaluated in the temperature ranges of 200-800oC and 200-900oC. Systematic methods for control of temperatures within the predetermined range and measurement of load applied to specimens as a function of temperature during thermal cycles have been established. Thermal fatigue tests were conducted under fully constrained condition, where both ends of specimens were completely fixed. Thermal fatigue property of STS 304 was superior to that of STS 429EM. Load relaxation behavior at the temperatures of thermal cycle was closely related with the thermal fatigue property.

scholarly journals Using Fatigue Characteristics to Analyse Test Results for 16Mo3 Steel under Tension-Compression and Oscillatory Bending Conditions

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1197 ◽  
Author(s):  
Andrzej Kurek
Keyword(s):  
Compression Test ◽  
Experimental Tests ◽  
Fatigue Tests ◽  
Test Method ◽  
Fatigue Properties ◽  
Test Results ◽  
Bending Tests ◽  
Fatigue Characteristics ◽  
Cost Efficient ◽  
Plastic Components

In this study, 16Mo3 steel was analysed for fatigue tests under tension-compression and oscillatory bending conditions. The analysis involved a comparison of fatigue test results obtained using the Manson-Coffin-Basquin, Langer and Kandil models and the models proposed by Kurek-Łagoda. It was observed that it is possible to substitute the basic tension-compression test performed in large testing machines with oscillatory bending tests carried out on a simple, modern test stand. The tests were performed under oscillatory bending on a prototype machine. The testing of 16Mo3 steel proved that the best-known Mason-Coffin-Basquin fatigue characteristic describes the results of all of the experimental tests very well, but the model can only be used when it is possible to divide strains into elastic and plastic components. It should be emphasised here that there is no such possibility in the case of tests performed under oscillatory bending conditions. It was proven that the proposed test method can substitute the tension-compression test very well and be a much more cost efficient way to obtain LCF material fatigue properties.

Fatigue Properties of Aluminium Alloys for Uniaxial Cyclic Loads

2014 ◽  
Vol 598 ◽  
pp. 13-19
Author(s):  
Ewelina Böhm ◽  
Tadeusz Łagoda
Keyword(s):  
Fatigue Strength ◽  
Chemical Composition ◽  
Aluminium Alloys ◽  
Cyclic Fatigue ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Cyclic Loads ◽  
Fatigue Characteristics

The paper presents an analysis of aluminium and its alloys in terms of fatigue strength. The paper contains information in terms of cyclic fatigue tests of aluminium alloys. On the basis of available literature data, Basquin fatigue characteristics have been designated. On their basis a comparison between chosen fatigue characteristics of aluminium alloys with different chemical composition and element percentage in the substance have been done.

Influence of Technology of Hot Forming of Plates from Aluminum Alloys Al-Cu-Li-Zn and Al-Zn-Mg-Cu on Resistance to Fatigue Fracture

2020 ◽  
Vol 22 (4) ◽  
pp. 94-109
Author(s):  
Kirill Zakharchenko ◽  
◽  
Vladimir Kapustin ◽  
Alexey Larichkin ◽  
Yaroslav Lukyanov ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Aluminum Alloys ◽  
Fatigue Fracture ◽  
Fatigue Failure ◽  
Strength Properties ◽  
Fatigue Tests ◽  
Measuring System ◽  
Fatigue Properties ◽  
Thick Plates ◽  
Pressure Shaping

Introduction. One of the primary objectives in the development of promising aircraft products is to reduce the weight of the aircraft structure. This problem can be solved by applying new low density materials such as aluminum alloys alloyed with lithium (for example, Al-Cu-Li-Zn) in the design of parts. The use of these materials in aircraft construction is limited by the processing technology, which must be such as not to damage the material and not reduce its strength properties. Such technologies include processing by pressure with heating, when creep processes are activated and the material passes into a state close to superplasticity. The purpose of the work: assessment of the effect of pressure shaping of aluminum alloys Al-Cu-Li-Zn and Al-Zn-Mg-Cu in creep mode on strength. The paper investigates the influence of the technology of pressure shaping of aluminum alloys Al-Cu-Li-Zn and Al-Zn-Mg-Cu on the resistance to fatigue failure. The work uses a method that allows to determine the ultimate stresses using diagrams of the accumulation of irreversible deformations; method of forming thick plates (40 mm) in the creep mode. The previously selected optimum temperatures for forming the plates are used. A non-contact coordinate measuring system is used to perform surface inspection after shaping. Fractography of the fracture of samples of alloy Al-Cu-Li-Zn and Al-Zn-Mg-Cu after fatigue failure is performed. Mathematical modeling of the deformation process of plates in creep mode is carried out in the MSC.Marc package. As a result, a conservative evaluation of the endurance limit for aluminum alloys Al-Cu-Li-Zn and Al-Zn-Mg-Cu is obtained. The shaping of thick plates in the creep mode is carried out. More than 80% of the board surface is formed with a deviation of less than 1 mm from the target size. Fatigue tests of samples made of molded panels of alloys Al-Cu-Li-Zn and Al-Zn-Mg-Cu are carried out, fatigue curves are plotted. The fractography of the surface of the fatigue fracture showed the presence of oxides in the samples of alloy Al-Cu-Li-Zn, in contrast to alloy Al-Zn-Mg-Cu. The results of fatigue tests are discussed, showing that the characteristics of the technological process of shaping and heat treatment do not deteriorate the fatigue properties of the investigated alloys. Comparative tests show that alloy Al-Cu-Li-Zn has higher fatigue characteristics. Mathematical modeling show that the use of the Boyle-Norton steady-state creep law is not enough to describe the process of plate forming. The necessity of setting the inverse problem of creep age forming is noted, where the coordinates of the punches of the loading device should act as boundary conditions.

Fatigue Properties and Design Criteria of a Gamma Titanium Aluminide Alloy

2011 ◽  
Vol 465 ◽  
pp. 531-534 ◽  
Author(s):  
Stefano Beretta ◽  
Mauro Filippini ◽  
Luca Patriarca ◽  
Giuseppe Pasquero ◽  
Silvia Sabbadini
Keyword(s):  
Titanium Aluminide ◽  
Electron Beam Melting ◽  
Room Temperature ◽  
Tial Alloy ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Gamma Titanium Aluminide ◽  
Titanium Aluminide Alloy ◽  
Fatigue Characteristics

The fatigue properties of a Ti-48Al-2Cr-2Nb alloy obtained by electron beam melting (EBM) with a patented process has been examined by conducting high cycle fatigue tests performed at different loading ratios both at room temperature and at high temperatures, comparable to those experienced by the components during service. Some tests have been conducted in the superlong life regime well exceeding 10 million cycles, highlighting individual fatigue characteristics of the studied TiAl alloy.

Low Cycle Fatigue Tests With the Use of Miniaturized Test Specimens

2017 ◽  
Author(s):  
Jan Dzugan ◽  
Radek Prochazka ◽  
Pavel Konopik
Keyword(s):  
Residual Life ◽  
Low Cycle Fatigue ◽  
Fem Analysis ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Treatment Development ◽  
Structured Materials ◽  
Testing Procedures ◽  
Large Application

Determination of mechanical properties with the use of sub-sized specimens is topic a high interest nowadays. The application of the sub-sized samples is quite wide for all cases where only limited amount of the experimental material is available such as evaluation of additively manufactured products properties, residual life of in-service components, properties determination of developed nano-structured materials, assessment of dilatometric samples used for thermal and thermo-mechanical treatment development, local properties of components, weld joints and so on. Concerning this large application field it would be very useful to prepare standard for small size samples especially for the most demanded material properties: tensile properties, notch impact transition temperature, fatigue properties, fracture toughness and creep. Current paper is going to deal with the low fatigue (LCF) properties assessment with the use of miniaturized specimens’. There were proposed specimen geometries with the use of FEM analysis and testing procedures for considered mini-specimens tests were developed. In the case of strain controlled LCF tests, contactless testing system had to be established for testing of small sized specimens, where it is not possible to apply standard mechanical extensometers for test control. Moreover, LCF procedure for high temperature tests was also successfully established here. The LCF results were subsequently used for Manson-Coffin parameters determination. Results of low cycle tests for several steels are confronted with the results of standard sized specimens with very good agreement for all considered conditions.

Experimental analysis of constant-amplitude fatigue properties in 6156 (Al-Mg-Si) sheet aluminum alloy

2018 ◽  
Vol 53 (8) ◽  
pp. 676-686
Author(s):  
Nikolaos D Alexopoulos ◽  
Evangelos Migklis ◽  
Dimitrios Myriounis
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Aluminum Alloys ◽  
Work Hardening ◽  
Endurance Limit ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Constant Amplitude ◽  
The Matrix ◽  
Fatigue Endurance

Fatigue mechanical behavior of wrought aluminum alloy (Al-Mg-Si) 6156 at T4 temper is experimentally investigated. Constant-amplitude fatigue tests, at fixed stress ratio R = 0.1, were carried out, and the respective stress–life diagram was constructed and compared against the competitive 6xxx aluminum alloys, for example, 6082 and 6061. Fatigue endurance limit of AA6156 was found to be approximately 155 ± 5 MPa, that is, almost 30% below yield stress Rp of the material. AA6156 presents almost 50% higher fatigue life in the high-cycle fatigue area and approximately 20% higher fatigue endurance limit, when compared with other 6xxx series aluminum alloys. Significant work hardening was induced due to fatigue and was experimentally validated by the measurements of residual stiffness of fatigue loops as well as of absorbed energy per fatigue loop. Work-hardening exponent was essentially decreased by almost 25% from the first fatigue cycles and up to 10% of fatigue life. Fracture surfaces of specimens loaded at applied stresses close to fatigue endurance limit exhibited signs of coarse voids due to the formed precipitates at the matrix. The fracture mechanism was a mixture of transgranunal and intergranular fracture for the fatigue specimens tested at higher applied fatigue loadings.

FATIGUE STRENGTH IMPROVEMENT BY PEENING TREATMENT IN DEGASSING PROCESSED CAST ALUMINUM ALLOYS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3593-3598 ◽  
Author(s):  
YASUO OCHI ◽  
KIYOTAKA MASAKI ◽  
TAKASHI MATSUMURA ◽  
YOHEI KUMAGAI ◽  
TATSUHIKO HAMAGUCHI ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Aluminum Alloys ◽  
Shot Peening ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Laser Peening ◽  
Cast Aluminum ◽  
Cast Aluminum Alloys ◽  
Rotating Bending Fatigue ◽  
Cast Alloys

Rotating bending fatigue tests were carried out in order to investigate effects of shot peening and laser peening treatment on fatigue properties of degassing processed cast aluminum alloys. Degassing was useful for decreasing cast defects and increasing the range of fatigue life and fatigue strength at 107 cycles compared with those of non-degassed cast alloys. The shot peening and the laser peening treatments also showed remarkable effects for increasing the resistance of crack propagation behaviors and improving the fatigue strength of the degassing processed cast aluminum alloys.

Characteristics of Repair Welds on Aged 2.25Cr-1Mo Steel for Creep and Creep-Fatigue Applications

2004 ◽  
Author(s):  
Yoshio Takagi ◽  
Shigeru Otsuki ◽  
Takuya Ito ◽  
Isamu Nonaka
Keyword(s):  
Weld Metal ◽  
Base Metal ◽  
Weak Link ◽  
Fem Analysis ◽  
Fatigue Tests ◽  
Coarse Grained ◽  
Fatigue Properties ◽  
Strain Concentration ◽  
Fine Grained ◽  
Creep Fatigue

The creep and the creep-fatigue properties of full repair welds (FRW) and partial repair welds (PRW) were evaluated in this study. Since the PRW contained the service-aged girth weld which was the weak link of the cross weld, the PRW was a shorter creep strength than the FRW. Moreover, the PRW showed a remarkably shorter creep-fatigue life compared to that of the FRW. In order to consider the poor creep-fatigue properties of PRW, finite element (FEM) analysis was conducted with experimentally measured material constants using service-aged base metal, aged weld metal, simulated coarse-grained HAZ, simulated fine-grained HAZ and repair weld metal. The analysis revealed that the strain concentrated on the aged and softened base metal or girth weld metal of the repair-welded cross weld specimen and not on the virgin cross weld specimen. The failure locations in creep-fatigue tests were close to the strain concentrated zone. Thus, the strain concentration is considered to work as a significant role and dominate the creep-fatigue properties of repair welds. In addition, the ductility of the weld metal was much less than that of the base metal. Consequently, the interaction of the strain concentration and the lack of ductility induced the lesser creep-fatigue properties of the PRW.

scholarly journals The Influence of the Strain and Stress Gradient in Determining Strain Fatigue Characteristics for Oscillatory Bending

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 173 ◽  
Author(s):  
Andrzej Kurek ◽  
Justyna Koziarska ◽  
Tadeusz Łagoda
Keyword(s):  
Aluminum Alloys ◽  
Compression Test ◽  
Strain Gradient ◽  
Stress Gradient ◽  
Fatigue Tests ◽  
Model Verification ◽  
Bending Test ◽  
Stress And Strain ◽  
Fatigue Characteristics ◽  
Gradient Surface

In this study, we created a new model to determine strain fatigue characteristics obtained from a bending test. The developed model consists of comparing the stress and strain gradient surface ratio for bending and tensile elements. For model verification, seven different materials were examined based on fatigue tests we conducted, or data available in the literature: 30CrNiMo8, 10HNAP, SM45C, 16Mo3 steel, MO58 brass, and 2017A-T4 and 6082-T6 aluminum alloys. As a result, we confirmed that the proposed method can be used to determine strain fatigue characteristics that agree with the values determined on the basis of a tensile compression test.

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