Tensile Deformation and Fracture in a Bulk Nanostructured Al-5083/SiCp Composite at Elevated Temperatures

2007 ◽  
Vol 29-30 ◽  
pp. 245-248
Author(s):  
F. Tang ◽  
B.Q. Han ◽  
Masuo Hagiwara ◽  
Julie M. Schoenung
Keyword(s):  
Elevated Temperatures ◽  
Tensile Deformation ◽  
Tensile Tests ◽  
Nanostructured Composite ◽  
Sic Particles ◽  
Deformation And Fracture ◽  
Ultrafine Grained ◽  
Al 5083 Alloy

An ultrafine-grained Al-5083 alloy reinforced with 5 vol.% nano-sized β-SiC particles was fabricated with a powder cryomilling and consolidation technique. Tensile tests were conducted at temperatures from 298 to 773 K for this composite. The mechanisms for deformation and fracture of this nanostructured composite at various temperatures are discussed.

In Situ Testing and Heterogeneity of UFG Cu at Elevated Temperatures

2015 ◽  
Vol 1127 ◽  
pp. 67-72
Author(s):  
Martin Petrenec ◽  
Petr Král ◽  
Jiří Dvořák ◽  
Milan Svoboda ◽  
Vàclav Sklenička
Keyword(s):  
Elevated Temperature ◽  
Tensile Test ◽  
Grain Growth ◽  
Elevated Temperatures ◽  
Tensile Deformation ◽  
Constant Strain Rate ◽  
Electron Back Scatter Diffraction ◽  
Coarse Grained ◽  
Ultrafine Grained

Experiments were conducted to investigate deformation-induced processes during in-situ tensile test at elevated temperature. Consequently the microstructure after creep loading was examined by 3D Electron Back Scatter Diffraction (EBSD) technique. The billets of coarse-grained copper were processed by equal-channel angular pressing (ECAP) at room temperature using a die that had an internal angle of 90° between the two parts of the channel and an outer arc of curvature of ~ 20°, where these two parts intersect. The pressing speed was 10 mm/min. To obtain an ultrafine-grained (UFG) material, the billets were subsequently pressed by route Bc by 8 ECAP passes to give the mean grain size ~ 0.7 μm. The constant strain-rate test in tension was performed at 473 K using testing GATAN stage Microtest 2000EW with EH 2000 heated grips which is configured for in-situ electron back scatter diffraction (EBSD) observations. Microstructure was examined by FEG-SEM TESCAN MIRA 3 XM equipped by EBSD detector HKL NordlysMax from OXFORD INSTRUMENT. The tensile test was interrupted by fast stress reductions after different deformation step and observation of microstructure changes was performed. Despite of a considerable interest in ECAP processing method, there are not many works documenting microstructure evolution and changes during creep testing and determining creep mechanisms of ultrafine-grained materials processed by ECAP. It was found that creep resistance of UFG pure Al and Cu is considerably improved after one ECAP pass in comparison with coarse grained material, however, further repetitive pressing leads to a noticeable deterioration in creep properties of ECAP material. Recently it was observed the coarsening of the grains in microstructure of ECAP copper during creep at elevated temperature. It was suggested that creep behaviour is controlled by storage and dynamic recovery of dislocations at high-angle boundaries. In the present work was found that ultrafine-grained microstructure is instable and significant grain growth has already occurred during heating to the testing temperature. Static recrystallization during heating led to the formation of high fraction of special boundaries Σ3 and Σ9. The tensile deformation at 473 K led to the additional grain growth and formation of new grains. Microstructure was investigated also by 3D EBSD.

scholarly journals Tensile Deformation and Fracture Mechanism of Bulk Bimodal Ultrafine-Grained Al-Mg Alloy

2009 ◽  
Vol 41 (4) ◽  
pp. 795-801 ◽  
Author(s):  
Zonghoon Lee ◽  
Velimir Radmilovic ◽  
Byungmin Ahn ◽  
Enrique J. Lavernia ◽  
Steven R. Nutt
Keyword(s):  
Fracture Mechanism ◽  
Tensile Deformation ◽  
Mg Alloy ◽  
Deformation And Fracture ◽  
Ultrafine Grained

scholarly journals The Investigation of Microstructure and Mechanical Behavior and the Fractographic Analysis of the Ti49.1Ni50.9 Alloy in States with Different Activation Deformation Volumes

2021 ◽  
Vol 11 (7) ◽  
pp. 3052
Author(s):  
Anna Churakova ◽  
Dmitry Gunderov ◽  
Elina Kayumova
Keyword(s):  
Mechanical Behavior ◽  
Test Temperature ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Fractographic Analysis ◽  
Coarse Grained ◽  
Ultrafine Grained ◽  
Coarse Grained State ◽  
Different Temperatures

In this article, the microstructure and mechanical behavior of the Ti49.1Ni50.9 alloy with a high content of nickel in a coarse-grained state, obtained by quenching, ultrafine-grained (obtained through the equal-channel angular pressing (ECAP) method) and nanocrystalline (high pressure torsion (HPT) + annealing), were investigated using mechanical tensile tests at different temperatures. Mechanical tests at different strain rates for determining the parameter of strain rate sensitivity m were carried out. Analysis of m showed that with an increase in the test temperature, an increase in this parameter was observed for all studied states. In addition, this parameter was higher in the ultrafine-grained state than in the coarse-grained state. The activation deformation volume in the ultrafine-grained state was 2–3 times greater than in the coarse-grained state at similar tensile temperatures. Fractographic analysis of samples after mechanical tests was carried out. An increase in the test temperature led to a change in the nature of fracture from quasi-brittle–brittle (with small pits) at room temperature to ductile (with clear dimples) at elevated temperatures. Microstructural studies were carried out after the tensile tests at different temperatures, showing that at elevated test temperatures, the matrix was depleted in nickel with the formation of martensite twins.

scholarly journals In Situ Observation of the Tensile Deformation and Fracture Behavior of Ti–5Al–5Mo–5V–1Cr–1Fe Alloy with Different Microstructures

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5794
Author(s):  
Suping Pan ◽  
Mingzhu Fu ◽  
Huiqun Liu ◽  
Yuqiang Chen ◽  
Danqing Yi
Keyword(s):  
Plastic Deformation ◽  
Fracture Behavior ◽  
Tensile Deformation ◽  
Lamellar Microstructure ◽  
Tensile Tests ◽  
In Situ Observation ◽  
Bimodal Microstructure ◽  
Deformation And Fracture ◽  
Deformation Processes

The plastic deformation processes and fracture behavior of a Ti–5Al–5Mo–5V–1Cr–1Fe alloy with bimodal and lamellar microstructures were studied by room-temperature tensile tests with in situ scanning electron microscopy (SEM) observations. The results indicate that a bimodal microstructure has a lower strength but higher ductility than a lamellar microstructure. For the bimodal microstructure, parallel, deep slip bands (SBs) are first noticed in the primary α (αp) phase lying at an angle of about 45° to the direction of the applied tension, while they are first observed in the coarse lath α (αL) phase or its interface at grain boundaries (GBs) for the lamellar microstructure. The β matrix undergoes larger plastic deformation than the αL phase in the bimodal microstructure before fracture. Microcracks are prone to nucleate at the αp/β interface and interconnect, finally causing the fracture of the bimodal microstructure. The plastic deformation is mainly restricted to within the coarse αL phase at GBs, which promotes the formation of microcracks and the intergranular fracture of the lamellar microstructure.

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