Evolution of microstructure in Ti15Mo alloy deformed by high pressure torsion during linear heating

Experiments were conducted on copper subjected to High Pressure Torsion to investigate the evolution of microstructure and microhardness with shear strain, γ. Observations have been carried out in the longitudinal section for a proper demonstration of the structure morphology. An elongated dislocation cell/subgrain structure was observed at relatively low strain level. With increasing strain, the elongated subgrains transformed into elongated grains and finally into equiaxed grains with high angle grain boundaries. Measurements showed the hardness increases with increasing γ then tends to saturations when γ >5. The variation tendency of microhardness with γ can be simulated by Voce-type equation.

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Evolution of microstructure and hardness during artificial aging of an ultrafine-grained Al-Zn-Mg-Zr alloy processed by high pressure torsion

Journal of Materials Science ◽

10.1007/s10853-020-05264-4 ◽

2020 ◽

Vol 55 (35) ◽

pp. 16791-16805

Author(s):

Jenő Gubicza ◽

Moustafa El-Tahawy ◽

János L. Lábár ◽

Elena V. Bobruk ◽

Maxim Yu Murashkin ◽

...

Keyword(s):

High Pressure ◽

Dislocation Density ◽

Grain Boundaries ◽

Artificial Aging ◽

High Pressure Torsion ◽

Secondary Phase ◽

Aging Effect ◽

Angular Pressing ◽

Ultrafine Grained ◽

Evolution Of Microstructure

Abstract An ultrafine-grained (UFG) Al-4.8%Zn-1.2%Mg-0.14%Zr (wt%) alloy was processed by high pressure torsion (HPT) technique and then aged at 120 and 170 °C for 2 h. The changes in the microstructure due to this artificial aging were studied by X-ray diffraction and transmission electron microscopy. It was found that the HPT-processed alloy has a small grain size of about 200 nm and a high dislocation density of about 8 × 1014 m−2. The majority of precipitates after HPT are Guinier–Preston (GP) zones with a size of ~ 2 nm, and only a few large particles were formed at the grain boundaries. Annealing at 120 and 170 °C for 2 h resulted in the formation of stable MgZn2 precipitates from a part of the GP zones. It was found that for the higher temperature the fraction of the MgZn2 phase was larger and the dislocation density in the Al matrix was lower. The changes in the precipitates and the dislocation density due to aging were correlated to the hardness evolution. It was found that the majority of hardness reduction during aging was caused by the annihilation of dislocations and some grain growth at 170 °C. The aging effect on the microstructure and the hardness of the HPT-processed specimen was compared to that observed for the UFG sample processed by equal-channel angular pressing. It was revealed that in the HPT sample less secondary phase particles formed in the grain boundaries, and the higher amount of precipitates in the grain interiors resulted in a higher hardness even after aging.

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Evolution of microstructure and hardness in aluminum processed by High Pressure Torsion Extrusion

Materials Science and Engineering A ◽

10.1016/j.msea.2019.138074 ◽

2019 ◽

Vol 762 ◽

pp. 138074 ◽

Cited By ~ 1

Author(s):

Babak Omranpour ◽

Yulia Ivanisenko ◽

Roman Kulagin ◽

Lembit Kommel ◽

E. Garcia Sanchez ◽

...

Keyword(s):

High Pressure ◽

High Pressure Torsion ◽

Evolution Of Microstructure

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A comparative study on the evolution of microstructure and hardness during monotonic and cyclic high pressure torsion of CoCuFeMnNi high entropy alloy

Journal of Materials Research ◽

10.1557/jmr.2018.479 ◽

2019 ◽

Vol 34 (5) ◽

pp. 732-743 ◽

Cited By ~ 4

Author(s):

Reshma Sonkusare ◽

Nimish Khandelwal ◽

Pradipta Ghosh ◽

Krishanu Biswas ◽

Nilesh Prakash Gurao

Keyword(s):

High Pressure ◽

Comparative Study ◽

High Pressure Torsion ◽

High Entropy Alloy ◽

High Entropy ◽

Image Position ◽

Evolution Of Microstructure

Abstract

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Evolution of Microstructure and Microhardness in Ti-15Mo β-Ti Alloy Prepared by High Pressure Torsion

Materials Science Forum ◽

10.4028/www.scientific.net/msf.879.2555 ◽

2016 ◽

Vol 879 ◽

pp. 2555-2560 ◽

Cited By ~ 4

Author(s):

Kristína Václavová ◽

Josef Stráský ◽

Jozef Veselý ◽

Svetlana Gatina ◽

Veronika Polyakova ◽

...

Keyword(s):

Plastic Deformation ◽

High Pressure ◽

Dislocation Density ◽

Severe Plastic Deformation ◽

High Pressure Torsion ◽

Positron Annihilation Spectroscopy ◽

Equivalent Strain ◽

Ti Alloys ◽

Evolution Of Microstructure ◽

Metastable Beta

The main aim of this study is to analyze the effect of the severe plastic deformation (SPD) on the mechanical properties and defect structure of metastable beta Ti alloys. Experiments were performed on two different β-Ti alloys: Ti-15Mo and Ti-6.8Mo-4.5Fe-1.5Al which were subjected to severe plastic deformation (SPD) by high pressure torsion (HPT). The increase of hardness with increasing equivalent strain was determined by microhardness mapping. Dislocation density was studied by advanced techniques of positron annihilation spectroscopy (PAS). Microhardness and dislocation density increases with increasing equivalent strain inserted by severe plastic deformation.

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