On the origin of extremely high strength of ultrafine-grained Al alloys produced by severe plastic deformation

Ultrafine-grained Al alloys produced by high pressure torsion are found to exhibit a very high strength, considerably exceeding the Hall-Petch predictions for the ultrafine grains. The phenomena can be attributed to the unique combination of ultrafine structure and deformation-induced segregations of solute elements along grain boundaries, which may affect the emission and mobility of intragranular dislocations

PHYSICAL SIMULATION OF COLD ROLLING OF ULTRA-FINE GRAINED AL 5083 ALLOY TO STUDY MICROSTRUCTURE EVOLUTION

Abstract. Recent investigations have demonstrated that ultra-fine grained (UFG) Al 5xxx alloys have a significant potential for industrial applications due to their enhanced mechanical and functional properties. The Al 5xxx alloys often have to undergo hot/cold rolling metalforming operations for fabrication of near-net shape products since they are widely used in form of sheets in marine, transport, and chemical engineering. The development of hot/cold rolling routes for the UFG metallic materials are very expensive due to much higher cost of the UFG metallic materials and time consuming due to numerous experimental trials. The objective of this work is to perform physical simulation of cold rolling of the UFG Al 5083 alloy obtained via equal channel angular pressing with parallel channels and to analyze the effect of cold rolling on the microstucture and microhardness of the material. It is demonstrated that physical simulation of metalforming processes for the UFG metallic materials can significantly reduce the amount of material required for development of processing routes and increase the efficiency of experimental work

The nature of influence of reinforcing element distribution on superplastic deformation behavior of a metal matrix composite

yesIn the composite with uniform distribution of the whiskers the spacing between surfaces of CGBS in units of average matrix grain size is slightly less than in the another state of the composite. In addition, the occurrence of grain boundary sliding was observed to decrease. The origin of high strain rate superplasticity (HSRS) in metal matrix composites (MMC) is discussedBelgorod State Universit

The nature of influence of reinforcing element distribution on superplastic deformation behavior of a metal matrix composite

In the composite with uniform distribution of the whiskers the spacing between surfaces of CGBS in units of average matrix grain size is slightly less than in the another state of the composite. In addition, the occurrence of grain boundary sliding was observed to decrease. The origin of high strain rate superplasticity (HSRS) in metal matrix composites (MMC) is discussedyesBelgorod State Universit

On the origin of extremely high strength of ultrafine–grained Al alloys produced by severe plastic deformation

International audienceUltrafine–grained Al alloys produced by high pressure torsion are found to exhibit a very high strength, considerably exceeding the Hall–Petch predictions for the ultrafine grains. The phenomena can be attributed to the unique combination of ultrafine structure and deformation–induced segregations of solute elements along grain boundaries, which may affect the emission and mobility of intragranular dislocations

Low-Temperature Superplasticity and High Strength in the Al 2024 Alloy with Ultrafine Grains

This study aims to achieve an ultrafine-grained (UFG) Al 2024 alloy superplasticity at temperatures lower than the traditional ones for commercial Al alloys (400–500 °C). The UFG structure with a mean grain size of 100 nm produced in the alloy by high-pressure torsion at room temperature provided a very high strength—microhardness (HV0.1) of 286 ± 4, offset yield strength (σ0.2) of 828 ± 9 MPa, and ultimate tensile strength (σUTS) of 871 ± 6 MPa at elongation to failure (δ) of 7 ± 0.2%. Complex tensile tests were performed at temperatures from 190 to 270 °C and strain rates from 10−2 to 5 × 10−5 s−1, and the values of flow stress, total elongation and strain rate-sensitivity coefficient were determined. The UFG alloy was shown to exhibit superplastic behavior at test temperatures of 240 and 270 °C. For the first time, 400% elongation was achieved in the alloy at an unusually low temperature of 270 °C (0.56 Tm) and strain rate of 10−3 s−1. The UFG 2024 alloy after superplastic deformation was found to have higher strength (150–160 HV) than that after the standard strengthening heat treatment T6