Effect of Rolling on Mechanical Properties and Fatigue Behavior of an Al-Mg-Sc-Zr Alloy

2014 ◽  
Vol 794-796 ◽  
pp. 331-336 ◽  
Author(s):  
Daria Zhemchuzhnikova ◽  
Rustam Kaibyshev

An aluminum alloy with a chemical composition of Al–6%Mg–0.35%Mn–0.2%Sc–0.08%Zr–0.07%Cr (in wt.) was rolled up to different reductions of 75, 88 and 95% at 360oC and at ambient temperature. The static mechanical properties and the high-cyclic fatigue (HCF) life were examined. It was shown that the hot rolling results in increased yield stress (YS) and ultimate tensile strength (UTS). However, ductility and fatigue limit of the hot rolled alloy and initial as-cast ingot are nearly the same. The combination of hot and cold rolling leads to significant improvement of tensile strength and fatigue resistance, while ductility tends to reduce with increasing the rolling reduction. The cold rolled alloy exhibits the endurance limit under fatigue conditions, while the alloy in the both as-cast and hot rolled conditions exhibits only fatigue strength. The effect of the deformation structure on the mechanical properties is discussed.

2014 ◽  
Vol 354 ◽  
pp. 175-181
Author(s):  
Abdulhamid Al-Abduljabbar ◽  
O.S. Es-Said

The purpose of this study is to characterize the effects of heat damage on the electrical conductivity and static mechanical properties of aluminum alloys. The data resulting from the experiments of thermal exposure of several aluminum alloys are used to model the relations that describe the dependence of the electrical conductivity and hardness on the two main variables of these experiments: the temperature and the time of exposure. The dependence of yield strength and ultimate tensile strength on hardness values is characterized. For each case, different materials (alloys) exhibit similar general trends although there are different coefficients for each material to satisfy the general relation.


2014 ◽  
Vol 794-796 ◽  
pp. 365-370
Author(s):  
Sergey Malopheyev ◽  
Sergey Mironov ◽  
Vladislav Kulitskiy ◽  
Rustam Kaibyshev

Effect of friction stir welding (FSW) on mechanical properties and microstructure of Al-5.4Mg-0.2Sc-0.1Zr sheets with ultra-fined grained (UFG) structure was studied. The UFG-sheets were produced by equal-channel angular pressing (ECAP) followed either by cold or hot rolling. FSW was found to be very effective for retaining the UFG microstructure as well as constituent coherent nano-scale dispersoids in the welded material. Despite the preservation effect, however, the essential material softening was observed in the weld zone. This was attributed to the recrystallization occurring during FSW. The joint efficiency for yield strength of the obtained friction stir welds was found to be 81% in the hot rolled condition and only 55% in the cold rolled state. The relatively low joint efficiency was associated with the recrystallization softening as well as with the formation of a specific “kissing bond” defect in the stir zone. The joint efficiency is believed may be improved by adjusting of welding conditions and/or tool design.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Y. Liu ◽  
Qiutong Li ◽  
Xiujie Jiang ◽  
Huan Liu ◽  
Xianpu Yuan ◽  
...  

This paper aimed to study the effect of material static mechanical properties on the fatigue crack initiation life of ω-shaped rail fastening clips, in which the Vossloh 300-1 fastener system was taken as an example. The static mechanical properties of 38Si7 steel (the material of the clip) were first investigated through a series of uniaxial tensile tests. According to the experimental outcomes, a classic assembly system was simulated afterwards using the finite element analysis (FEA) method. On the basis of the Brown–Miller criterion, an in-depth numerical study regarding the critical plane was realized, which allowed fatigue crack initiation to be successfully reproduced by FEA. Finally, a detailed parametric study was performed with the relevant sensitivity analysis. The results showed that the initiation and progression of fatigue cracks in the fastening clip occur in the plane of the maximum shear strain. The fatigue crack initiation life of the fastening clip was extremely sensitive to the elastic modulus, especially more sensitive to the tensile strength. From an engineering viewpoint, the fatigue resistance of the fastening clip could be boosted by (i) increasing the tensile strength of the material to at least 1450 MPa and (ii) rendering the elastic modulus smaller than 160 GPa.


2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Qiang Wu ◽  
Kunning Fu ◽  
Ruizhi Wu ◽  
Jinghuai Zhang ◽  
Legan Hou ◽  
...  

The as-cast Mg-14Li-1Zn alloy was hot rolled at different temperatures with the reduction of 50%, followed by cold rolling with the reduction of 80%. The effects of the hot rolling temperature on the microstructure and mechanical properties of the final specimens were investigated. The results show that the higher rolling temperature brings about a more homogeneous microstructure, which is favorable for the subsequent cold rolling. When the hot rolling temperature is 300°C, the final specimen possesses the highest tensile strength and hardness of 238 MPa and 67.7 HV, respectively. When the hot rolling temperature is 200°C, the final specimen possesses the highest elongation of 24.6%.


2019 ◽  
Vol 11 (10) ◽  
pp. 2962 ◽  
Author(s):  
Guohui Zhang ◽  
Xiaohang Li ◽  
Zongli Li

This paper presents an experiment to investigate the influence of moisture on the static mechanical properties of concrete, and prediction equations for strength and fracture toughness of concrete at different strength grades, relative to water saturation, were established respectively. The research results show that all of the compressive strength, splitting tensile strength, and fracture toughness of concrete exhibit an approximately linearly decreasing trend with the increase in water saturation. For saturated concrete specimens with w/c 0.65, 0.55, 0.42 compared with dry ones, compressive strength decreases by 40.08%, 36.08%, and 33.73%, respectively, splitting tensile strength decreases by 45.39%, 42.61%, and 35.18%, respectively, and fracture toughness decreases by 57.31%, 49.92%, and 46.76%, respectively. The higher the water saturation of concrete, the larger the slope of the ascending part of the uniaxial compressive stress-strain curve, and the smaller the peak strain corresponding to the peak compressive stress, then in this case, both crack mouth opening displacement and loading point deflection corresponding to the critical load on three-point bending beam, decrease. Ingress of water causes the deformation capacity to decrease, and the toughness to weaken, which are unfavorable to the mechanical properties of concrete.


1998 ◽  
Vol 31 (1-2) ◽  
pp. 43-52 ◽  
Author(s):  
L. Q. Chen ◽  
Y. X. Lü ◽  
C. S. Lee ◽  
J. Bi ◽  
R. K. Y. Li

A study has been made on the mechanical properties of an aluminum alloy matrix (Al–3.0wt% Cu–1.5 wt% Mg–0.4wt% Mn)composites reinforced with a volume fraction of 15% silicon carbide under hot- and cold-rolling conditions. The preferred crystallite orientation distribution functions (ODFs) of these rolled sheets were measured. The tensile test results showed that the ultimate tensile strength and plasticity of the hot-rolled composite sheet are better than those of the cold-rolled one. However, the cold-rolled sheet specimen exhibits much higher 0.2% offset yield strength than that in the case of hot rolling. The cold-rolling texture of this sheet composite is obtained from the development of hot-rolled texture only by a little rotation about the related axes. It consists of random texture and three weak components, {001}〈110〉, {110}〈112〉 and {3314}〈773〉, while the hot rolling texture of the metal-matrix composite (MMC) sheet is almost random under the rolling reduction employed. The preferred grain orientation has effect on the yield strength and no much influence on the ultimate tensile strength of the cold rolled sheet. The decrease in the ultimate tensile strength of the cold-rolled specimen is mainly attributed to the micro-damages in the microstructure produced during cold rolling.


Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 476
Author(s):  
Sayed Amer ◽  
Ruslan Barkov ◽  
Andrey Pozdniakov

Microstructure of Al-Cu-Yb and Al-Cu-Gd alloys at casting, hot-rolled -cold-rolled and annealed state were observed; the effect of annealing on the microstructure was studied, as were the mechanical properties and forming properties of the alloys, and the mechanism of action was explored. Analysis of the solidification process showed that the primary Al solidification is followed by the eutectic reaction. The second Al8Cu4Yb and Al8Cu4Gd phases play an important role as recrystallization inhibitor. The Al3Yb or (Al, Cu)17Yb2 phase inclusions are present in the Al-Cu-Yb alloy at the boundary between the eutectic and aluminum dendrites. The recrystallization starting temperature of the alloys is in the range of 250–350 °C after rolling with previous quenching at 590 and 605 °C for Al-Cu-Yb and Al-Cu-Gd, respectively. The hardness and tensile properties of Al-Cu-Yb and Al-Cu-Gd as-rolled alloys are reduced by increasing the annealing temperature and time. The as-rolled alloys have high mechanical properties: YS = 303 MPa, UTS = 327 MPa and El. = 3.2% for Al-Cu-Yb alloy, while YS = 290 MPa, UTS = 315 MPa and El. = 2.1% for Al-Cu-Gd alloy.


Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 968
Author(s):  
Dong Xing ◽  
Xinzhou Wang ◽  
Siqun Wang

In this paper, Berkovich depth-sensing indentation has been used to study the effects of the temperature-dependent quasi-static mechanical properties and creep deformation of heat-treated wood at temperatures from 20 °C to 180 °C. The characteristics of the load–depth curve, creep strain rate, creep compliance, and creep stress exponent of heat-treated wood are evaluated. The results showed that high temperature heat treatment improved the hardness of wood cell walls and reduced the creep rate of wood cell walls. This is mainly due to the improvement of the crystallinity of the cellulose, and the recondensation and crosslinking reaction of the lignocellulose structure. The Burgers model is well fitted to study the creep behavior of heat-treated wood cell walls under different temperatures.


Author(s):  
Antao Deng ◽  
Bin Ji ◽  
Xiang Zhou

A new geometric design method for foldcores based on the generalized Resch patterns that allow face-to-face bonding interfaces between the core and the skins is proposed. Based on the geometric design method, a systematic numerical investigation on the quasi-static mechanical properties of the generalized Resch-based foldcores made of carbon fiber-reinforced plastic (CFRP) woven fabrics subjected to compression and shear loads is performed using the finite element method that is validated by experiments. The relationships between the mechanical properties and various geometric parameters as well as laminate thickness of the generalized Resch-based CFRP foldcores are revealed. Additionally, the mechanical properties of the generalized Resch-based CFRP foldcore are compared to those of the standard Resch-based, Miura-based foldcore, the honeycomb core, and the aluminum counterpart. It is found that the generalized Resch-based CFRP foldcore performs more stably than the honeycomb core under compression and has higher compressive and shear stiffnesses than the standard Resch-based and Miura-based foldcores and absorbs as nearly twice energy under compression as the Miura-based foldcore does. When compared with the aluminum counterpart, the CFRP model has higher weight-specific stiffness and strength but lower energy absorption capacity under shearing. The results presented in this paper can serve as the useful guideline for the design of the generalized Resch-based composite foldcore sandwich structures for various performance goals.


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