An investigation of deformed microstructure and mechanical properties of Zircaloy-4 processed through multiaxial forging

Fuloria, Devasri; Nageswararao, P.; Jayaganthan, R.; Jha, S.K.; Srivastava, D.

doi:10.1016/j.matchemphys.2015.09.025

Cited by 8 publications

(3 citation statements)

References 35 publications

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“…However, with respect to magnesium alloy the SPD processing is usually performed at elevated temperatures due to its low ductility of hexagonal structure [ 25 ]. Among various SPD techniques, multi-pass forging is frequently used since this procedure is capable of producing homogeneous fine-grained microstructures in bulk materials with large dimensions [ 26 , 27 ]. Furthermore, the thickness and diameter of the sample can be kept after multi-pass forging, which is different from conventional thermal deformation.…”

Section: Introductionmentioning

confidence: 99%

The Comparison in the Microstructure and Mechanical Properties between AZ91 Alloy and Nano-SiCp/AZ91 Composite Processed by Multi-Pass Forging Under Varying Passes and Temperatures

et al. 2019

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In this study, both AZ91 alloy and nano-SiCp/AZ91 composite were subjected to multi-pass forging under varying passes and temperatures. The microstructure and mechanical properties of the alloy were compared with its composite. After six passes of multi-pass forging at a constant temperature of 400 ℃, complete recrystallization occurred in both the AZ91 alloy and composite. The decrease of temperature and the increase of passes for the multi-pass forging led to further refinement of dynamic recrystallized grains and dynamic precipitation of second phases. The grain size of the nano-SiCp/AZ91 composite was smaller than that of the AZ91 alloy under the same multi-pass forging condition, which indicated that the addition of SiC nanoparticles were beneficial to grain refinement by pinning the grain boundaries. The texture intensity for the 12 passes of multi-pass forging with varying temperatures was increased compared with that after nine passes. The ultimate tensile strength is slightly decreased while the yield strength was increased unobviously for the AZ91 alloy with the decrease of temperature and the increase of the passes for the multi-pass forging. Under the same condition of multi-pass forging, the yield strength of the composite was higher than that of the AZ91 alloy due to the Orowan strengthening effect and grain refinement strengthening resulting from externally applied SiC nanoparticles and internally precipitated second phases. By comparing the microstructure and mechanical properties between the AZ91 alloy and nano-SiCp/AZ91 composite, the strength-toughness properties of the composites at room temperature were affected by the matrix grain size, texture evolution, SiC nanoparticles distribution and the precipitated second phases.

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Section: Introductionmentioning

confidence: 99%

The Comparison in the Microstructure and Mechanical Properties between AZ91 Alloy and Nano-SiCp/AZ91 Composite Processed by Multi-Pass Forging Under Varying Passes and Temperatures

et al. 2019

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“…With respect to bulk materials, it is more effective to obtain exceptional grain refinement using severe plastic deformation (SPD) with large accumulated strain and abundant material flow, which is different from that by conventional thermal deformation [ 19 , 20 , 21 , 22 ]. Among various SPD procedures, multi-pass forging is particularly promising for fabricating large piece of material, an advantage that is mainly attributed to its special process [ 23 , 24 , 25 , 26 , 27 ]. The sample shape can be kept during multi-pass forging, while thickness and diameter usually reduce after conventional thermal deformation.…”

Section: Introductionmentioning

confidence: 99%

Development of SiC Nanoparticles and Second Phases Synergistically Reinforced Mg-Based Composites Processed by Multi-Pass Forging with Varying Temperatures

et al. 2018

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In this study, SiC nanoparticles were added into matrix alloy through a combination of semisolid stirring and ultrasonic vibration while dynamic precipitation of second phases was obtained through multi-pass forging with varying temperatures. During single-pass forging of the present composite, as the deformation temperature increased, the extent of recrystallization increased, and grains were refined due to the inhibition effect of the increasing amount of dispersed SiC nanoparticles. A small amount of twins within the SiC nanoparticle dense zone could be found while the precipitated phases of Mg17Al12 in long strips and deformation bands with high density dislocations were formed in the particle sparse zone after single-pass forging at 350 °C. This indicated that the particle sparse zone was mainly deformed by dislocation slip while the nanoparticle dense zone may have been deformed by twinning. The yield strength and ultimate tensile strength of the composites were gradually enhanced through increasing the single-pass forging temperature from 300 °C to 400 °C, which demonstrated that initial high forging temperature contributed to the improvement of the mechanical properties. During multi-pass forging with varying temperatures, the grain size of the composite was gradually decreased while the grain size distribution tended to be uniform with reducing the deformation temperature and extending the forging passes. In addition, the amount of precipitated second phases was significantly increased compared with that after multi-pass forging under a constant temperature. The improvement in the yield strength of the developed composite was related to grain refinement strengthening and Orowan strengthening resulting from synergistical effect of the externally applied SiC nanoparticles and internally precipitated second phases.

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“…Although it is used in nuclear plants since the 1970 s, research in the recent years has been quite active on this material. Much work is devoted to irradiation effects [4], possible effects of a hypothetical loss of coolant accident [5], mechanical properties [6] related to the crystallographic anisotropy of the final product [7] or to multiaxial forging [8].…”

Section: Introductionmentioning

confidence: 99%

Influence of the size of the prior β grains on the microstructure of β quenched Zircaloy-4

Ammar

Darrieulat

Aoufi

2018

Metall. Res. Technol.

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This work deals with the influence on Zircaloy-4 of annealing in the β domain and subsequent quenching in view of extrusion. The effect of the size of the prior β grains on the microstructure is investigated. The results indicate that for prior β grain sizes up to 1.6 mm, the β quenched Widmanstätten microstructure is distributed between “parallel platelets” and “basket-weave”. However, sizes larger than 2 mm promote the formation of “basket-weave”. Double annealing in the β domain leads to the formation of large prior β grains with no need to anneal for a long time. Indeed, protracted annealing may lead to exaggerated growth. Efficient double annealing requires some conditions: rate of cooling after the first β annealing a few °C.s−1 (air cooling), heating rates of 1 or 2 °C.s−1 during the second rise in temperature. The second cooling should be somewhat quicker (possibly 12 °C.s−1 and above) to obtain the thin, intricate lamellae favored for extrusion.

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An investigation of deformed microstructure and mechanical properties of Zircaloy-4 processed through multiaxial forging

Cited by 8 publications

References 35 publications

The Comparison in the Microstructure and Mechanical Properties between AZ91 Alloy and Nano-SiCp/AZ91 Composite Processed by Multi-Pass Forging Under Varying Passes and Temperatures

The Comparison in the Microstructure and Mechanical Properties between AZ91 Alloy and Nano-SiCp/AZ91 Composite Processed by Multi-Pass Forging Under Varying Passes and Temperatures

Development of SiC Nanoparticles and Second Phases Synergistically Reinforced Mg-Based Composites Processed by Multi-Pass Forging with Varying Temperatures

Influence of the size of the prior β grains on the microstructure of β quenched Zircaloy-4

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