scholarly journals Study of the Microstructure and Crack Evolution Behavior of Al-5Fe-1.5Er Alloy

2018 ◽  
Author(s):  
Ming Li ◽  
Zhiming Shi ◽  
Xiufeng Wu ◽  
Huhe Wang ◽  
Yubao Liu
Keyword(s):  
Crack Initiation ◽  
Tensile Tests ◽  
Eutectic Structure ◽  
Interface Structure ◽  
Crack Evolution ◽  
Binding Ability ◽  
Initiation And Propagation ◽  
The Matrix ◽  
Evolution Behavior

The microstructure of Al-5Fe-1.5Er alloy was characterized and analyzed by using XRD, SEM, TEM and EDS. The effect of microstructure on the behavior of crack initiation and propagation was investigated by in situ tensile testing. Results show that the microstructure consists of α-Al matrix, Al3Fe, Al4Er, eutectic phase Al3Fe + Al4Er, while the 1.5 wt.% Er was added in Al-5Fe alloy. The twin structure of the Al3Fe phase was observed, and the twin plane is {001}. Moreover, a continuous concave and convex interface structure of the Al4Er has been found. Al3Fe is in the form of a sheet with a clear gap inside.In situ tensile tests of the alloy at room temperature show that the crack initiation occured mainly in the Al3Fe phase, and that the crack propagation modes include intergranular and transgranular expansion. Crack transgranular expansion is due to the strong binding ability between Al4Er phases and surrounding organization, and the continuous concave and convex interface structure of the Al4Er provides a significant meshing effect on the matrix and eutectic structure.

scholarly journals Study of the Microstructure and Crack Evolution Behavior of Al-5Fe-1.5Er Alloy

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 172 ◽  
Author(s):  
Ming Li ◽  
Zhiming Shi ◽  
Xiufeng Wu ◽  
Huhe Wang ◽  
Yubao Liu
Keyword(s):  
Electron Microscopy ◽  
Crack Initiation ◽  
Tensile Tests ◽  
Eutectic Structure ◽  
Interface Structure ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Evolution Behavior

In this work, the microstructure of Al-5Fe-1.5Er alloy was characterized and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) techniques. The effect of microstructure on the behavior of crack initiation and propagation was investigated using in situ tensile testing. The results showed that when 1.5 wt.% Er was added in the Al-5Fe alloy, the microstructure consisted of α-Al matrix, Al3Fe, Al4Er, and Al3Fe + Al4Er eutectic phases. The twin structure of Al3Fe phase was observed, and the twin plane was {001}. Moreover, a continuous concave and convex interface structure of Al4Er was observed. Furthermore, Al3Fe was in the form of a sheet with a clear gap inside. In situ tensile tests of the alloy at room temperature showed that the crack initiation mainly occurred in the Al3Fe phase, and that the crack propagation modes included intergranular and trans-granular expansions. The crack trans-granular expansion was due to the strong binding between Al4Er phases and surrounding organization, whereas the continuous concave and convex interface structure of Al4Er provided a significant meshing effect on the matrix and the eutectic structure.

Synthesis, Microstructure, and Mechanical Properties of FeCo-VC Composites

2006 ◽  
Vol 980 ◽  
Author(s):  
Hongbin Bei ◽  
E. P. George
Keyword(s):  
Mechanical Properties ◽  
Cast Alloy ◽  
Tensile Tests ◽  
Eutectic Structure ◽  
Directionally Solidified ◽  
Quaternary Alloys ◽  
The Matrix ◽  
Solid Solution Matrix ◽  
Solution Matrix

AbstractFe-Co-V-C quaternary alloys were drop cast and directionally solidified to obtain an in situ composite. It is found that the fully eutectic structure occurs at a composition of Fe - 40.5Co -10.4V- 8.6C (at. %) in a drop-cast alloy. Directional solidification of this composition in a high-temperature optical floating zone furnace produces a well-aligned microstructure, consisting of sub-micron VC fibers (~19% by volume) embedded in a FeCo-5V solid solution matrix containing ~ 1% C. The temperature dependencies of mechanical properties of this composite were examined by tensile tests and the composite was found to have higher yield strength and lower ductility than the matrix.

Mechanical Properties of 91% Tungsten Alloy

2007 ◽  
Vol 345-346 ◽  
pp. 1625-1628 ◽  
Author(s):  
Wei Dong Song ◽  
Hai Yan Liu ◽  
Jian Guo Ning
Keyword(s):  
Crack Initiation ◽  
Tensile Tests ◽  
Tungsten Alloy ◽  
Test Results ◽  
Bending Tests ◽  
Three Point Bending ◽  
Grain Sizes ◽  
Initiation And Propagation ◽  
Fracture Behaviors ◽  
The Matrix

The tensile tests and the three-point bending tests have been conducted to investigate the crack initiation and propagation and the fracture behavior of 91W-6.3Ni-2.7Fe with three kinds grain sizes of 1~3μm, 10~15μm and 30~40μm. SEM was introduced to analyze the grain sizes, the micro-defects, the deformations and the fracture behaviors of tungsten alloys. The test results show that under the same loading conditions, the crack initiation and the crack propagation are not only related to grain size, but also related to the contiguity of tungsten grains and the interface between the tungsten grains and the matrix.

Influence of Striker Shape on the Crack Initiation and Propagation on Laterally Impacted Thin Aluminium Plates

2013 ◽  
Author(s):  
Bin Liu ◽  
Richard Villavicencio ◽  
C. Guedes Soares
Keyword(s):  
Crack Initiation ◽  
Failure Modes ◽  
Testing Machine ◽  
Tensile Tests ◽  
Impact Testing ◽  
Small Scale ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
The Matrix ◽  
Force Displacement

Experimental and numerical results of drop weight impact tests are presented, examining the plastic response and the crack initiation and propagation of small-scale clamped rectangular aluminium plates laterally impacted by different indenter shapes. The experiments are conducted using a fully instrumented impact testing machine. The shape of the deformation of the specimens and the process of initiation and propagation of the material fracture is presented. The obtained force-displacement responses show a good agreement with the simulations performed by the LS-DYNA finite element solver. The strain hardening of the material is defined using experimental data of quasi-static tensile tests and the critical failure strain is evaluated measuring the thickness and the width at fracture of the tensile test pieces. The results show that the absorbed energy to perforate the specimens is highly sensitive to the shape of the striker. Thus, the crack propagation for each striker type is analysed in terms of the force-displacement response. The failure modes are described by the matrix of the infinitesimal strain tensors and the shape of the deformation of the failing elements.

SEM In Situ Investigation on Fatigue Cracking Behavior of X80 Pipeline Steel with Inclusions

2011 ◽  
Vol 284-286 ◽  
pp. 1096-1100 ◽  
Author(s):  
Ke Tong ◽  
Yan Ping Zeng ◽  
Xin Li Han ◽  
Yao Rong Feng ◽  
Xiao Dong He
Keyword(s):  
Crack Initiation ◽  
Pipeline Steel ◽  
Fatigue Cracking ◽  
Fatigue Loading ◽  
In Situ Observation ◽  
X80 Pipeline Steel ◽  
Cracking Behavior ◽  
The Matrix ◽  
Extension Period

The micro-mechanical behavior of inclusions in X80 pipeline steel under fatigue loading was investigated by means of SEM in situ observation. The influence of sizes and shapes of inclusion on crack initiation and propagation was analyzed. The result shows that for large-size single-particle inclusion, cracks initiate from the interior under the fatigue loading. When a certain circulation cycles are reached, cracks initiate at the matrix near the sharp corner of the inclusion. The cracks extend at the matrix during the stable extension period and unstable extension period following the crack initiation, until fracture occurred. For chain inclusion, cracks first initiate at the interface between inclusion and matrix within the chain area, and the circulation cycles needed for initiation are far less than single inclusion. Cracks steadily extend after the initiation, and then fracture after very short circulation cycles. A chain of inclusion with the shape corners is serious harmful to the fatigue properties.

In-Situ Investigation of Initiation and Propagation Behavior of Bainitic Steels in Sour Environment

2018 ◽  
Author(s):  
Kyono Yasuda ◽  
Nobuyuki Ishikawa ◽  
Yutaka Matsui ◽  
Daisuke Mizuno ◽  
Tomoyuki Yokota
Keyword(s):  
Crack Initiation ◽  
Ultrasonic Inspection ◽  
Base Material ◽  
Propagation Rate ◽  
Cracking Behavior ◽  
Propagation Behavior ◽  
Initiation And Propagation ◽  
In Situ Investigation ◽  
Linepipe Steels

Hydrogen induced cracking (HIC) occurs by the poisoning effect of hydrogen sulfide (H2S) which promotes hydrogen absorption and entry at steel surface. Therefore, it is important for linepipe steels to have sufficient HIC resistance in sour environments. The HIC resistance is usually evaluated by measuring cracks after the standardized immersion test such as NACE TM0284. However, the general evaluation method cannot investigate HIC initiation and propagation behavior separately. It is necessary to understand the effect of metallurgical factors on the cracking behavior of sour service linepipe. In this study, in-situ ultrasonic inspection equipment was applied to the HIC test for the several linepipe steels with bainitic microstructure in order to clarify crack initiation and propagation behavior quantitatively. The three dimensional (3-D) distribution of cracks in the specimen was successfully captured as time sequence, and the temporal change of the crack area ratio (CAR) was investigated. It was revealed that the CAR-time curves are consist of four stages with different CAR increment rate. The first stage is the incubation of crack initiation. In the second stage, cracks occur and grow, and adjacent cracks coalesced rapidly. Regarding the first and second stages, sensitivity for the HIC initiation was well correlated with the hydrogen diffusion coefficient and the density of crack initiation site, such as MnS and Nb inclusions. In the third stage, the coalesced cracks propagate along the center segregation region. From the investigation of individual crack behavior, the crack along harder region showed higher propagation rate. In the fourth stage, the crack propagation rate was decreased to be in stasis. It can be stated that crack growth in the final stage is strongly affected by the hardness of base material and the crack easily propagate when HIC occurs in high strength steels.

Synchrotron X-Ray Topography of Dislocation Arrays

1986 ◽  
Vol 82 ◽  
Author(s):  
J. C. Bilello
Keyword(s):  
Thin Films ◽  
Plastic Deformation ◽  
Crack Initiation ◽  
Large Scale ◽  
Crack Initiation And Propagation ◽  
X Ray ◽  
Gaas Substrates ◽  
Initiation And Propagation ◽  
Dislocation Arrays

ABSTRACTThe application of relatively low resolution x-ray topography methods, typically ∿ 1 micrometer, is limited in studies which involve large scale dislocation networks. However, the ability to non-destructively image wide areas for “thick” specimens at high intensity with a tunable x-ray source makes the synchrotron an ideal probe for a range of problems previously inaccessible by other methods. Some examples will be discussed such as: (a) crack initiation and propagation in fatigued bicrystals, (b) real-time in situ plastic deformation studies in strain-annealed Mo crystals, and (c) strain distributions in vapor deposited and LPE thin films on Si and GaAs substrates.

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