On nanostructured molybdenumcopper composites produced by. A bulk sample of an almgsc alloy, in the form of a short cylinder with diameter of 10 mm and height of. After the hollow cone high pressure torsion hchpt, the thermal stability of zr64. High pressure torsion hpt is widely used as a severe plastic deformation technique to create ultrafinegrained structures with promising mechanical and functional properties. Processing was carried out using highpressure torsion at room temperature with no subsequent sintering treatment, producing a porosityfree, ultrafinegrained composite. Thermal stability of an mgnd alloy processed by high. These cavities allow on the one hand a centering of the sample for accurate torsional straining, and on the other hand a nearly hydrostatic pressure.
High pressure torsion hpt, as schematically shown in fig. The used setup has been described in detail in ref. The setup combines basic features of both split hopkinson torsion bar shtb and static high pressure torsion hpt devices. Pdf threedimensional analysis of plastic flow during. Incremental high pressure torsion as a novel severe plastic.
Ultrafinegrained materials fabrication with high pressure torsion. Mar 16, 2010 continuous high pressure torsion chpt was developed as an expeditious process to effect severe plastic deformation. Extensive deformation of the cu50mo50 composite via twostep highpressure torsion produced equiaxed nanoscale grains of mo and cu with a grain size of 1015 nm. The high pressure torsion hpt process total materia article. Recent studies showed that the method is effective not only for increasing the. Straumal bb, gornakova as, fabrichnaya ob, kriegel mj, mazilkin aa, baretzky b et al. Incremental high pressure torsion as a novel severe. Pdf highpressure torsion hpt method currently receives much attention as a. Its microstructure was analyzed by xray line profile analysis and transmission electron microscopy and its texture by xray microdiffraction. The evolution of microstructure, texture, and mechanical properties of an mg1. Such rotation is exerted after the compressive pressure is applied. Application of high pressure torsion to bulk samples.
Highpressure torsion hpt refers to the processing of metals whereby samples are subjected to a compressive force and concurrent torsional straining. Subsequently, microhardness and electrical resistivity of the cu samples are measured and correlated with the microstructure. Iron fe is commonly found in aluminum al, but its contents are usually kept as low as possible, because the formation of intermetallic phases may induce fracture. However, the application of hpt has been restricted to thin disk samples. Severe plastic deformation spd frequently induces phase transformations like decomposition of supersaturated solid solution, dissolution of precipitates, amorphization, nanocrystallization etc. Different models of hardness evolution in ultrafine. In this study, high pressure torsion hpt was used to control the microstructure in an al2 %fe alloy in conjunction with wire drawing and an aging treatment, in order to improve not only their mechanical properties but also the. Softening of high purity aluminum and copper processed by. The hpt processing is becoming more popular in these days as a powerful scientific tool to investigate the structural and multifunctional properties of bulk nanostructured materials. It was shown that, depending on the mechanical characteristics of original sample layers hardness of individual layers and their mechanical behavior and ability to hardening under. For a more realistic study of materials flowduring the test, a detailed model was presented here in.
Effects of highpressure torsion on the pitting corrosion. Evolution of microstructure and hardness in aluminum processed by high pressure torsion extrusion. In order to understanding the behavior of local deformation on disks after hpt, the process has been simulated by using finite element analysis method in abaqusexplicit software. High pressure torsion hpt is a well known procedure to obtain nano and submicrometer grained microstructures in bulk materials, e. However, it has certain size limitations, especially regarding the thickness of the processed samples. Severe plastic deformation spd techniques, such as highpressure torsion hpt,1 equalchannel angular press ing ecap1,2 and. High pressure torsion hpt is a severe plastic deformation process, which is widely used for producing nanocrystalline metals and alloys. Afterwards, the hptprocessed alloy was annealed for 1 h at temperatures ranging from 423 to 773 k and its mechanical properties and microstructural evolution were examined using microhardness measurements and electron backscattered diffraction ebsd analysis. Texture and microstructure formation in commercially pure. The equiatomic facecentered cubic high entropy alloy crmnfeconi was severely deformed at room and liquid nitrogen temperature by high pressure torsion up to shear strains of about 170. This article deals with the homogenization of metal matrix composites mmcs with inhomogeneous particle distribution by severe plastic deformation. Influence of highpressure torsion straining conditions on. High pressure torsion ti6al4v alloy volume fraction a b s t r a c t a coldrolled ti6al4v sheet was subjected to three different heat treatments prior to pro. Az91 magnesium alloy has been successfully processed at room temperature by highpressure torsion as well as at elevated temperatures.
In the high pressure torsion hpt method, as schemat ically shown in figure 1, a small disc sample or small amount of powder is squeezed between two anvils under high pressure and concurrently strained by rotating the lower anvil with respect to the upper anvil 1. Microstructure, texture, and strength development during high. Exceptional strengthening of biodegradable mgznca alloys. Thermal conductivity reduction of crystalline silicon by. Published under licence by iop publishing ltd iop conference series. High pressure phase transformations under severe plastic deformation by torsion in rotational anvils valery i. A subsequent heat treatment at temperatures of around 0. Developing highpressure torsion for use with bulk samples. However,experimental observations confirm that this is not typically the case. High pressure torsion hpt is historically the first and is currently most common process of the severe plastic deformation spd. In summary, we demonstrated a novel way to reduce the lattice thermal conductivity of crystalline silicon by intense plastic strain through high pressure torsion hpt at a pressure of 24 gpa. Microhardness measurements, after severe plastic deformation, were.
R kulagin 1, y beygelzimer 2, y ivanisenko 1, a mazilkin 1,3 and h hahn 1. Plastic deformation of batio3 ceramics by highpressure torsion and changes in phase transformations, optical and dielectric properties. Highpressure phase transformations under severe plastic. Examining the microhardness evolution and thermal stability. In curich cocu alloys the situation is even more interesting. It was reported that hpt produces grain sizes finer than those using other spd processes such as equalchannel angular pressing ecap. High pressure torsion htp is a popular physical simulator to produce ultrafine grained materials. Strain weakening and superplasticity in a bisn eutectic. Sorry, we are unable to provide the full text but you may find it at the following locations. Pdf evolution of microstructure and hardness in aluminum. Structure, phase composition, and microhardness of carbon.
The patterns of the structure formation in layered metallic materials under high pressure torsion processing are studied, and a physical model of the formation of multilayer structures in such materials is proposed. In this study, al606110 pct sic and al606120 pct al2o3 powder metallurgy pm mmcs with clustered particle distribution in the asfabricated condition are subjected to high pressure torsion hpt at room temperature. Results show that the plastic yield deformation was occurring during the hpt. High pressure torsion hpt is a wellknown procedure to impart severe plastic deformation spd into metallic materials. Effect of revolution on inhomogeneous deformation of if steel in high pressure torsion abstract fulltext html xml download as pdf size. Apr 20, 2016 the high pressure torsion process compacts the material under very high pressure between two plungers producing a very specific material microstructure. From a historical point of view, the principle of hpt was. Kaveh edalati, yuki ito, kenichiro suehiro, and zenji horita 2009. Microhardness distribution and finite element method analysis. Effect of revolution on inhomogeneous deformation of if. The effects of reducing the grain size by highpressure torsion hpt on the pitting corrosion resistance of alfe alloys with fe contents of 0. Fabrication of nanocomposites through diffusion bonding. Because of the significant microstructural changes during.
Highpressure torsion for fabrication of highstrength and. Highpressure torsion for new hydrogen storage materials. Materials science and engineering, volume 194, 7th international conference on nanomaterials by severe plastic deformation 27 july 2017, sydney. During the hpt process high plastic strains are realized, resulting in fully dense bulk materials with microstructures in the nanocrystalline nc andor ultrafine grained ufg size. Threedimensional analysis of plastic flow during high pressure torsion. Modelling of high pressure torsion using fem sciencedirect. High pressure torsion of aluminum with ultrahigh purity 99. A mathematical model of deformation under high pressure torsion. Experiments were conducted to examine the feasibility of extending conventional processing with highpressure torsion hpt from use with thin disks with thickness of 1 mm to bulk cylindrical samples with height of 8 mm. Close to the top and bottom surfaces of hpt disk, the 210. In this contribution incremental high pressure torsion is introduced as a novel severe plastic deformation process.
Phase transitions in cubased alloys under high pressure. Feb 25, 2015 high pressure torsion is known as one of the most popular severe plastic deformation processes. Using the chpt, sheets of high purity aluminum, copper, and iron were successfully processed by introducing intense shear strain under high pressure. High pressure torsion hpt refers to the processing of metals whereby samples are subjected to a compressive force and concurrent torsional straining. On the homogeneity of deformation by high pressure torsion. Ultrafine grained materials offer substantial advantage over coarser grained materials displaying higher strength and better ductility. The generally accepted theory of hpt is based on the assumptions of uniformity of simple shear deformation along the height of the specimen and that there is no slippage between the sample and the anvils. Effective temperature of high pressure torsion in zrnb alloys. The high pressure torsion hpt process total materia blog. New mgvcr bcc alloys synthesized by highpressure torsion. The high pressure torsion hpt process total materia.
Modeling strain and density distributions during high pressure torsion of precompacted powder materials. Jun 28, 2014 similarly, mechanical deformation using high pressure was adopted to improve the seeback coefficient of bi 2 te 3 and pbte 11, 12. Softening of high purity aluminum and copper processed by high pressure torsion. Using high pressure torsion for the coldconsolidation of copper. Fabrication of nanocomposites through diffusion bonding under high pressure torsion volume 33 issue 18 megumi kawasaki, jaekyung han, donghyun lee, jaeil jang, terence g. Using high pressure torsion to process an aluminummagnesium nanocomposite through diffusion bonding volume 31 issue 1 megumi kawasaki, byungmin ahn, hanjoo lee, alexander p. It is shown that all hardness values fall on a single curve when they are plotted against equivalent strain for both metals.
New mgvcr bcc alloys synthesized by highpressure torsion and ball milling. Although the fundamental principles of this procedure were first proposed more than 60 years ago, processing by hpt became of major importance. Since 2007, the method has been employed to enhance the hydrogenation kinetics in different mgbased hydrogen storage materials. The microstructures of the processed samples were examined by electron backscatter diffraction, and the mechanical properties were determined by vickers hardness and tensile testing. Homogenization of metal matrix composites by highpressure. Features of structure formation in layered metallic. Naghdy, texture and microstructure formation in commercially pure aluminum during high pressure torsion, 2017. Schematic view of the high pressure torsion process. Pressure torsion on microstructure, hardness and corrosion behavior for pure magnesium and different magnesium alloys claudio l. Highpressuretorsion deformation of meltspun nd9fe85b6 alloy. Dimensions of grains diminished considerably resulting in the decrease of the registered ae event rate by almost an order of magnitude.
Similarly, mechanical deformation using high pressure was adopted to improve the seeback coefficient of bi 2 te 3 and pbte 11, 12. The effect of temperature and degree of deformation upon severe plastic deformation by torsion under a high pressure on the structure, phase composition, and. The high pressure torsion process compacts the material under very high pressure between two plungers producing a very specific material microstructure. High pressure torsion hpt is an attractive processing method in severe plastic deformation techniques involving the application of high compressive pressure with concurrent torsional straining.
Pdf highpressure torsion of aluminum with ultrahigh. High pressure torsion during the constrained hpt process, the material experiences shear deformation between a fixed and a rotating anvil, without losing its original dimensions. Vickers microhardness is plotted as a function of the distance from the disk center and equivalent strain. Nanocrystallization in al85ce8ni5co2 amorphous alloy obtained by different strain rate during high pressure torsion. Pdf continuous highpressure torsion chpt was developed as an expeditious process to effect. Thermal conductivity reduction of crystalline silicon by high. Highpressure torsion processing of az91 magnesium alloy. The phase composition, mechanical properties, and microstructure of binary fec alloys with various carbon concentrations 0. Full texthtml download pdf 7606k download meta ris. View enhanced pdf access article on wiley online library html view download pdf for offline viewing. Production of nanograined intermetallics using highpressure. Abstracthigh pressure torsion hpt is widely used as a severe plastic deformation technique to create ultrafinegrained structures with promising mechanical and functional properties.
Pdf simultaneous improvement of strength and ductility in. Upscaling of the hpt deformation and the possibility of large. Simultaneously applying high pressure and torsion causes shear strain and thus enhancement of mechanical properties such as microhardness. High pressure torsion hpt can be traced back to the experiments that won percy bridgman the 1946 nobel prize in physics, though its use in metal processing is.
A sketch of the idealized hpt process is shown in fig. Deformationinduced supersaturation in immiscible material. Excellent grain refinement is anticipated when using this technique to average grain sizes of the submicrometer or even nanometer ranges. In this study, two biodegradable mgznca alloys with alloy content of less than 1 wt % were strengthened via high pressure torsion hpt. A hardness of more than 110 hv and tensile strength of more than 300 mpa were achieved in mg0. High pressure torsion is known as one of the most popular severe plastic deformation processes. Dual mechanisms of grain refinement in a fecocrni high. Apr 21, 2017 an equiatomic fecocrni high entropy alloy with a facecentered cubic structure was fabricated by a powder metallurgy route, and then processed by high pressure torsion. Commercial purity cp titanium was processed by high pressure torsion hpt under an applied pressure of 6.
This chapter examines the various publications describing the experimental studies of the effect of hpt on the mechanical behaviors and alterations of microstructural. Modeling strain and density distributions during high. Pdf generation and healing of porosity in high purity. Existingsolutions of hpt predict a zero deformation and grain refinement near its samples longitudinal axis. Pdf highpressure torsion driven phase transformations. After processing, there were significant but systematic variations in the values of the vickers microhardess throughout the sample with the highest hardness. The grain boundary size decreases to nanoscale levels upon increasing the strain by hpt processing. High pressure torsion hpt processing was applied to cast pure magnesium, and the effects of the deformation on the microstructure, hardness, tensile properties and corrosion resistance were evaluated. Generation and healing of porosity in high purity copper by highpressure torsion article pdf available in materials characterization 145 august 2018 with 117 reads how we measure reads. The results of hardness measurements after chpt were well consistent with those of chpt using disk and ring specimens. Strain weakening and superplasticity in a bisn eutectic alloy processed by highpressure torsion view the table of contents for this issue, or go to the journal homepage for more.