scholarly journals Study of Bending Fatigue Properties of Al-Si Cast Alloy

2017 ◽  
Vol 62 (3) ◽  
pp. 1591-1596 ◽  
Author(s):  
E. Tillová ◽  
D. Závodská ◽  
L. Kuchariková ◽  
M. Chalupová ◽  
J. Belan
Keyword(s):  
Cast Alloy ◽  
Fatigue Crack Initiation ◽  
Solution Treatment ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Casting Defects ◽  
Casting Condition ◽  
Bending Fatigue ◽  
Eutectic Si ◽  
Size And Morphology

AbstractFatigue properties of casting Al-alloys are very sensitive to the microstructural features of the alloy (e.g. size and morphology of the eutectic Si, secondary dendrite arm spacing - SDAS, intermetallics, grain size) and casting defects (porosity and oxides). Experimental study of bending fatigue properties of secondary cast alloys have shown that: fatigue tests up to 106-107cycles show mean fatigue limits of approx. 30-49 MPa (AlSi9Cu3 alloy - as cast state), approx. 65-76 MPa (AlSi9Cu3 alloy after solution treatment) and 60-70 MPa (self-hardened AlZn10Si8Mg alloy) in the tested casting condition; whenever large pore is present at or near the specimen’s surface, it will be the dominant cause of fatigue crack initiation; in the absence of large casting defects, the influence of microstructural features (Si morphology; Fe-rich phases) on the fatigue performance becomes more pronounced.

Effect of Plasma Nitriding on Ultra-High Cycle Fatigue Behaviors of Ti-6Al-4V

2011 ◽  
Vol 295-297 ◽  
pp. 2386-2389 ◽  
Author(s):  
Ren Hui Tian ◽  
Qiao Lin Ouyang ◽  
Qing Yuan Wang
Keyword(s):  
High Cycle Fatigue ◽  
Plasma Nitriding ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Ultra High Cycle Fatigue ◽  
Stress Ratios

In order to investigate the effect of plasma nitriding treatment on fatigue behavior of titanium alloys, very high cycle fatigue tests were carried out for Ti-6Al-4V alloy using an ultrasonic fatigue machine under load control conditions for stress ratios of R=-1 at frequency of ƒ=20KHz. Experiment results showed that plasma nitriding treatment played the principal role in the internal fatigue crack initiation. More importantly, plasma nitriding treatment had a detrimental effect on fatigue properties of the investigated Ti-6Al-4V alloy, and the fatigue strength of material after plasma nitriding treatment appeared to be significantly reduced about 17% over the untreated material.

Effects of Water Jet Peening and Hardening Treatment on Fatigue Properties of SCr420

2009 ◽  
Author(s):  
Akira Shimamoto ◽  
Ryo Kubota ◽  
Sung-mo Yang ◽  
Dae-kue Choi ◽  
Weiping Jia
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Water Jet ◽  
Fatigue Properties ◽  
In Situ Observation ◽  
Axial Tensile ◽  
High Pressure Water Jet

An experimental study of high pressure water jet peening treatment on chromium steal SCr420 H3V2L2 is conducted to study the effects of cavitation impacts of high-speed water on fatigue crack initiation and propagation of notched specimens. There are six different kinds of specimens. First three kinds are treated with; only annealing, only water quenching, and only oil quenching. Other three kinds are treated with above heat treatment and water jet peening, respectively. An axial tensile fatigue tests’ condition is 260MPa maximum stress amplitude, 0 stress ratio and 10Hz frequency, while in-situ observation by SEM is employed. Although fatigue life of the specimens with annealing and water jet peening is shorter than that of only annealing, fatigue life of water and oil quenching with water jet peening specimens is obviously longer than those without water jet peening treatment. Water jet peening has increased residual stress inside the specimens on the latter case and raised their fatigue strength. In-situ observation on the crack tips approves above analysis.

Transformation of Fe-rich intermetallic phases and eutectic Si morphology in Al–Si–Cu–Fe cast alloy with solution treatment

2019 ◽  
Vol 6 (6) ◽  
pp. 066515
Author(s):  
Bo Jiang ◽  
Ze-Sheng Ji ◽  
Hong-Yu Xu ◽  
Mao-Liang Hu ◽  
Yong-Bing Zhang ◽  
...  
Keyword(s):  
Cast Alloy ◽  
Solution Treatment ◽  
Intermetallic Phases ◽  
Eutectic Si

Effect of Heat Treatment on Microstructure and Thermal Fatigue Properties of Al-Si-Cu-Mg Alloys

2018 ◽  
Vol 37 (4) ◽  
pp. 289-298
Author(s):  
Wei Chao ◽  
Liu Guang-lei ◽  
Wan Hao ◽  
Li Yu-shan ◽  
Si Nai-chao
Keyword(s):  
Heat Treatment ◽  
Fatigue Crack ◽  
Crack Initiation ◽  
Grain Boundary ◽  
Crack Propagation ◽  
Thermal Fatigue ◽  
Fatigue Crack Initiation ◽  
Fatigue Properties ◽  
Eutectic Si ◽  
Al Matrix

AbstractThe effect of heat treatment on the microstructure and thermal fatigue properties were studied by means of optical microscope (OM) and scanning electron microscope (SEM). Energy dispersive X-ray detector (EDX) was used to analyze the role of phase composition in fatigue crack propagation. The results show that after heat treatment, the ultimate tensile strength increased from 285 MPa to 368 MPa and the elongation increased from 5.8 % to 6.5 %. During the initiation of fatigue crack, the crack was mainly propagated through eutectic Si area. With the long needles of eutectic Si particles spherodized after heat treatment, the split action from brittle Si particles to α-Al matrix was reduced and prolonged the fatigue crack initiation period. After aging for 6 h, the dispersed precipitation of secondary phases (Al2Cu, Mg2Si) elevated the driving force of crack propagation, blocked the spread of crack in the grain boundary, decreased the rate of fatigue crack growth and improved the fatigue resistance of alloy at the same time. In the process of crack initiation, the surplus-phase around the grain boundary fell off from α-Al matrix under thermal cycling stresses. The combination of interfaces was weaken by cycling stress and the fatigue crack was finally grown up in the weakness area between matrix and secondary phase.

Improvement of Fatigue Properties in a Cast Aluminum Alloy by Roller Burnishing and Friction Stir Processing

2014 ◽  
Vol 891-892 ◽  
pp. 662-667 ◽  
Author(s):  
Yuki Nakamura ◽  
Masaki Nakajima ◽  
Hiroaki Masuda ◽  
Toshifumi Kakiuchi ◽  
Yoshihiko Uematsu
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Friction Stir Processing ◽  
Compressive Residual Stress ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Bending Fatigue ◽  
Friction Stir

Roller burnishing (RB) and friction stir processing (FSP) were applied to a cast aluminum alloy, AC4CH-T6 (equivalent to A356-T6), to improve the fatigue properties. In roller burnished specimens, Vickers hardness was increased until the depth of 60μm compared with that of the as-cast specimens, resulting in work-hardening by RB. The compressive residual stress on the surface of the roller burnished specimens was also increased from 35MPa to 132MPa. In order to investigate the effect of RB on the fatigue properties, rotary bending fatigue tests have been performed using the roller burnished and the as-cast specimens. The roller burnished specimens exhibited higher fatigue strength than the untreated specimens. It is due to the increase in hardness and compressive residual stress by RB. In addition, plane bending fatigue tests have been performed using the friction stir processed and untreated specimens. Fatigue strengths of the friction stir processed specimens were highly improved compared with untreated specimens as the results of the elimination of casting defects by FSP. However, the crack growth rates of the friction stir processed specimens were faster than those of untreated specimens. It is due to the softening of the material by heat input during the FSP.

Fatigue Properties of Nitride Cr-Mo Steel with CrN Thin Film Deposited by Aip Method

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1554-1559 ◽  
Author(s):  
Daisuke Yonekura ◽  
Atsushi Tsukuda ◽  
Ri Ichi Murakami ◽  
Koji Hanaguri
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Fatigue Strength ◽  
Film Thickness ◽  
Compressive Residual Stress ◽  
Optical Microscope ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Three Point Bending

In this study, we selected the nitride Cr-Mo Steel SCM435 as the substrate. Attention was focussed on the effect of film thickness. The Arc Ion Plating was performed using Cr cathode and N2 gas. The specimens were prepared for the film thickness 6, 12 and 18μm The three point bending fatigue tests were performed at room temperature in a laboratory environment. After the fatigue test, crack initiation sites were examined by using an optical microscope and a scanning electron microscope. The results obtained were as follows: (1) A high compressive residual stress generated in the film, and the compressive residual stress of 12μm film thickness was the greatest. (2) The fatigue strength of coated specimens for thin film was slightly lower than for substrate. (3) The film thickness hardly affected the fatigue strength of coated specimens.

Contact and bending fatigue behaviour of austempered ductile iron gears

2017 ◽  
Vol 232 (6) ◽  
pp. 998-1008 ◽  
Author(s):  
Carlo Gorla ◽  
Edoardo Conrado ◽  
Francesco Rosa ◽  
Franco Concli
Keyword(s):  
Ductile Iron ◽  
Contact Fatigue ◽  
Research Programme ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Austempered Ductile Iron ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Metallurgical Analysis ◽  
Single Tooth

In the present paper a research programme aimed at investigating both the bending and contact fatigue properties of an austempered ductile iron applied to gears is presented, in order to determine reliable values of the limits, which take into account the influence of the production process, to be applied in the design of gearboxes. The bending fatigue tests are performed according to the single tooth fatigue approach and the pitting tests are performed with a back-to-back rig. Metallurgical analysis is performed on the failed specimens, in order to understand the origin and the propagation of the failures and to appreciate the influence of the micro-structure on the performances obtained.

scholarly journals Fatigue Characteristics of Materials Used in Transport Industry Applications

2019 ◽  
Vol 1 (1) ◽  
pp. 810-818
Author(s):  
Juraj Belan ◽  
Lenka Kuchariková ◽  
Magdalena Mazur ◽  
Eva Tillová ◽  
Mária Chalupová
Keyword(s):  
Cast Alloy ◽  
Human Life ◽  
Low Frequency ◽  
Fatigue Tests ◽  
Point Of View ◽  
Fatigue Properties ◽  
Major Interest ◽  
Transport Industry ◽  
Industry Applications ◽  
Materials Used

AbstractDesigners have a major interest about fatigue properties of materials used in transport industry. Each component in transport works under alternating stress. From this point of view the fatigue properties are important for single parts lifetime resulting into safety of whole components as cars and airplanes what leads to safety on the roads or air and have influence on human life as well. Therefore this paper deals with fatigue properties of wrought Inconel alloy IN 718 and aluminum cast alloy AlSi9Cu3. Both materials were put on fatigue push – pull test, but Ni – based IN 718 alloy at frequency of loading around 20 000 kHz (High Frequency High Cycles Fatigue) and aluminum alloy AlSi9Cu3 at frequency of loading around 80 Hz (Low Frequency High Cycles Fatigue). These parameters were chosen with respect of usage such materials for production of components used in transport industry applications. Results after fatigue tests are presented as Wohler curve. For prediction of source of fracture the SEM fractography analysis of fatigue fracture surfaces was made.

Fatigue Properties of a Low-Alloy Steel with a Nano-Structured Surface Layer Obtained by Severe Mechanical Treatments

2013 ◽  
Vol 577-578 ◽  
pp. 469-472 ◽  
Author(s):  
Seyyed Mostafa Hassani-Gangaraj ◽  
A. Moridi ◽  
Mario Guagliano
Keyword(s):  
Surface Layer ◽  
Alloy Steel ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Xrd Analysis ◽  
Processing Parameters ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Low Alloy Steel ◽  
Structured Surface

Recent development in mechanical technologies and processes have shown that by performing traditional mechanical treatments with unusual and severe parameters it is possible to obtain metal surfaces characterized by grain size with dimension in the order of 50-100 nm. This confers peculiar and superior properties to the surface layer of material. Since the surface is the usual point of fatigue crack initiation it is expected that the parts treated this way show a better fatigue behavior with respect to the coarse grain materials, even if treated with conventional mechanical treatments. This work explores any opportunities to obtain nano-structured surface layers by means of two popular mechanical treatments, shot peening and deep rolling. To this end particularly severe processing parameters are applied on a low alloy steel fatigue test specimens. The treated surface is characterized by means of optical Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) analysis of residual stress and roughness measurements. In the end a series of fatigue tests on smooth specimens severely treated, conventionally treated and not treated were executed. The results show the potential benefits of severe mechanical treatments and were interpreted in the light of peculiar effects of these novel treatments on the characteristics of the treated surfaces.

Fatigue Properties of Solution-Treated Type 304 Stainless Steel after Nitriding

2012 ◽  
Vol 525-526 ◽  
pp. 217-220
Author(s):  
Yuki Nakamura ◽  
Masaki Nakajima ◽  
Toshihiro Shimizu ◽  
Kentaro Suzuki ◽  
Yu Bai ◽  
...  
Keyword(s):  
Solid Solution ◽  
Stainless Steel ◽  
Martensitic Transformation ◽  
Fatigue Limit ◽  
Solution Treatment ◽  
Fatigue Tests ◽  
304 Stainless Steel ◽  
Fatigue Properties ◽  
Nacl Solution ◽  
Type 304

The solution treatment after nitriding (STAN) was performed to stabilize the γ- phase in a metastable austenitic stainless steel, type 304, and to improve the strength of type 304 by the solid solution of nitrogen. Plasma nitriding was conducted at 500°C for 8.5h, and then solution treatment was performed at 1200°C for 1h. As a result, the static strength and the hardness were improved by the STAN. Rotary bending fatigue tests were performed on the specimens with STAN (solid solution strengthened) together with the untreated and the nitrided ones in laboratory air and in 3%NaCl solution. In laboratory air, the fatigue strength of the solid solution strengthened specimen increased compared to that of the untreated specimens, where fatigue limits were 340MPa and 290MPa for the solid solution strengthened and the untreated, respectively. However, the fatigue limit of the solid solution strengthened specimen was lower than that of the nitrided specimen, that is, 380MPa. On the other hand, in 3%NaCl solution, the fatigue strengths of the nitrided specimens and the solid solution strengthened specimens decreased significantly compared to those in laboratory air. After the fatigue tests at the stress level of fatigue limit in laboratory air, the strain-induced martensitic transformation was examined by XRD. In the solid solution strengthened specimens, the strain-induced martensitic transformation was not detected during fatigue tests until 3x107 cycles, indicating that the γ- phase was stabilized by the solid solution of nitrogen.

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