- Email: [email protected]
Texture development of wire drawn Cu–Fe composites
Physb1=16409=Jayashree=Venkatachala=BG
Physica B 276}278 (2000) 888}889
Texture development of wire drawn Cu}Fe composites H.-G. Brokmeier *, R.E. Bolmaro, J.A. Signorelli, A. Fourty Institut fu( r Werkstowkunde und -technik der Techn. Univers. Clausthal, Clausthal, Germany Instituto de Fn& sica Rosario, Fac. de Ciencias Exactas, Ingeniern& a y Agrimensura, Universidad Nacional de Rosario, Rosario, Argentina
Abstract Polycrystalline models have shown to be powerful tools for prediction of texture developments which is mainly used to analyze textures of di!erent types of materials. When more than one phase is present, it is necessary to take into account their interaction because of their elastic and plastic co-deformation. We have considered wire drawn Cu}Fe samples with a well-de"ned microstructural state and relatively soft deformation steps of 0.25 equivalent Von Mises strains (VM) up to 3.0 VM. Both phases show typical FCC and BCC wire textures with a texture sharpness depending on the strain. Texture simulations using a 2-site viscoplastic self-consistent model as a constitutive equation in a fully 3D "nite element code give results in good qualitative agreement with the experimental ones. 2000 Elsevier Science B.V. All rights reserved. Keywords: Cu}Fe composite materials; Texture
1. Introduction Texture investigations in deformed composites provide a good means to obtain information about the deformation behavior. Studies has been made by means of Taylor-based models as well as 1 site and 2 site self-consistent simulations to describe deformation texture development in two-phase materials. The correlation between high accurate neutron di!raction measurements and di!erent texture simulations interprets on one side active slit systems and on the other side the reproduction of the texture sharpness. Cu}Fe composites belong to a group of composites on which an anomalous increase of the Young's modulus is observed. That means, the interest on Cu}Fe composites is mainly based on two points. First, Cu}Fe is an excellent model substance to investigate metal}matrix composites of FCC}BCC mixture. Second, applications are in discussion to use the anomalous properties of Cu}Fe and Cu}Nb composites. The systematic investigation on wire drawn Cu}Fe composites combines a comparison of * Correspondence address: GKSS-Forschungszentrum, Max-Planck-Str. Geb. 03, D-21501 Geesthacht, Germany. Tel.: #49-04152-871207; fax: #49-04152-871338. E-mail address: [email protected] (H.-G. Brokmeier)
di!erent quantitative texture software's with di!erent simulation models on soft, intermediate and strong deformed materials.
2. Experiment The samples were prepared by powder metallurgy starting with pure Cu and Fe powders. A mixture of 13 lm 75 vol.% Fe particles and 32 lm 25 vol% Cu [1] was homogenized and pre-compacted. Thereafter, hot extrusion to rods of 19.8 mm has a!orded the starting material for wire drawing. Wire drawing was stopped at every 0.25 equivalent Von Mises strains. According to di!erent deformations up to VM 3.0 we have obtained a set of 13 samples. Texture measurements were carried out at TEX-2, the texture di!ractometer at FGR-1, Geesthacht, Germany [2]. There are three main reasons to prefer neutrons instead of X-rays. First, is that neutron di!raction allows the measurement of complete pole "gures of cylindrical samples. Second, is the sample preparation which consists only on cutting the wires and "xing on a sample holder. Third, is that corrections can be reduced to background correction that high accurate texture data are obtained. This high accuracy is necessary for the deter-
0921-4526/00/$ - see front matter 2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 1 - 4 5 2 6 ( 9 9 ) 0 1 5 4 0 - 9
Physb=16409=Jaya=VVC=BG H.-G. Brokmeier et al. / Physica B 276}278 (2000) 888}889
Fig. 1. Texture development of the Fe texture (ISEM34 * iterative series expansion method with lmax"34; simulation by the 2-site viscoplastic self-consistent model with spin sharing).
mination of small texture variations. Based on the high symmetry of the wire drawing process the texture is axial symmetric. Consequently, one-dimensional pole "gures were measured to save counting time. A rotating sample holder was used to increase the grain statistics. Six pole "gures for each sample and three pole "gures for each phase were detected * Fe (1 1 0), (2 0 0) and (2 1 1); Cu (1 1 1), (2 0 0), (2 2 0).
889
normalization of the pole "gure. The best correlation was obtained between the experimental results and the iterative series expansion method using lmax"34. A very good agreement was reached by the 2-site self-consistent model [3] taking into account that both phases share there spin during deformation, see Fig. 1. Other simulations based on Taylor models or on viscoplastic selfconsistent models are able to describe the texture type but not the sharpness of the texture. The Fe-texture goes down for soft strains from 5.6 to 5.1 mrad (Von Mises strain of 0.50). By increasing strain the texture develops sharper continuously up to a Von Mises strain of 2.5. The texture decrease at increasing strain can be explained by a curling of Fe and Cu particles [1]. The Cu texture is much weaker than the Fe texture. In the case of the starting material the 11 0 02 texture component is the strongest which is originated by recrystallization of the hot extrusion. These component goes down continuously by increasing deformation. The development of the weaker 11 1 12 component looks similar to the Fe texture. Soft strain leads to a texture decrease followed by an increase of the texture sharpness up to a Von Mises strain to 2.5. The curling a!ects on both phases, Cu and Fe, and consequently the texture becomes weaker.
Acknowledgements 3. Results The starting material for this investigation, a hot extruded rod, shows in the case of Fe a 11 1 02 "ber texture with an orientation density of about 5.6 mrd. In the case of copper a double "ber was formed (11 0 02 with 5.4 mrad and 11 1 12 with 2.2 mrad). The texture development of these typical texture types for Fe and Cu were correlated to the deformation. Quantitative texture calculation was performed by di!erent versions of the series expansion method, by di!erent versions of the WIMV method and by MENTEX. All programs give su$cient results. In the case of the Fe-texture the orientation density of the 11 1 02 "ber can be calculated directly by
This project was funded by the German}Argentine Intergovernmental Agreement No. ARG 6 L1A 1A/2 and CONICET-Argentina. Neutron di!raction was supported by the German Ministry for Research and Foundation (BMBF-03BR4CLA7).
References [1] R. Beuse et al., Scripta Met. 27 (1992) 767. [2] H.-G. Brokmeier et al., Mater Sci. Forum 273}275 (1998) 277. [3] R.E. Bolmaro et al., Comput. Mater. Sci. 9 (1997) 237.
Physica B 276}278 (2000) 888}889
Texture development of wire drawn Cu}Fe composites H.-G. Brokmeier *, R.E. Bolmaro, J.A. Signorelli, A. Fourty Institut fu( r Werkstowkunde und -technik der Techn. Univers. Clausthal, Clausthal, Germany Instituto de Fn& sica Rosario, Fac. de Ciencias Exactas, Ingeniern& a y Agrimensura, Universidad Nacional de Rosario, Rosario, Argentina
Abstract Polycrystalline models have shown to be powerful tools for prediction of texture developments which is mainly used to analyze textures of di!erent types of materials. When more than one phase is present, it is necessary to take into account their interaction because of their elastic and plastic co-deformation. We have considered wire drawn Cu}Fe samples with a well-de"ned microstructural state and relatively soft deformation steps of 0.25 equivalent Von Mises strains (VM) up to 3.0 VM. Both phases show typical FCC and BCC wire textures with a texture sharpness depending on the strain. Texture simulations using a 2-site viscoplastic self-consistent model as a constitutive equation in a fully 3D "nite element code give results in good qualitative agreement with the experimental ones. 2000 Elsevier Science B.V. All rights reserved. Keywords: Cu}Fe composite materials; Texture
1. Introduction Texture investigations in deformed composites provide a good means to obtain information about the deformation behavior. Studies has been made by means of Taylor-based models as well as 1 site and 2 site self-consistent simulations to describe deformation texture development in two-phase materials. The correlation between high accurate neutron di!raction measurements and di!erent texture simulations interprets on one side active slit systems and on the other side the reproduction of the texture sharpness. Cu}Fe composites belong to a group of composites on which an anomalous increase of the Young's modulus is observed. That means, the interest on Cu}Fe composites is mainly based on two points. First, Cu}Fe is an excellent model substance to investigate metal}matrix composites of FCC}BCC mixture. Second, applications are in discussion to use the anomalous properties of Cu}Fe and Cu}Nb composites. The systematic investigation on wire drawn Cu}Fe composites combines a comparison of * Correspondence address: GKSS-Forschungszentrum, Max-Planck-Str. Geb. 03, D-21501 Geesthacht, Germany. Tel.: #49-04152-871207; fax: #49-04152-871338. E-mail address: [email protected] (H.-G. Brokmeier)
di!erent quantitative texture software's with di!erent simulation models on soft, intermediate and strong deformed materials.
2. Experiment The samples were prepared by powder metallurgy starting with pure Cu and Fe powders. A mixture of 13 lm 75 vol.% Fe particles and 32 lm 25 vol% Cu [1] was homogenized and pre-compacted. Thereafter, hot extrusion to rods of 19.8 mm has a!orded the starting material for wire drawing. Wire drawing was stopped at every 0.25 equivalent Von Mises strains. According to di!erent deformations up to VM 3.0 we have obtained a set of 13 samples. Texture measurements were carried out at TEX-2, the texture di!ractometer at FGR-1, Geesthacht, Germany [2]. There are three main reasons to prefer neutrons instead of X-rays. First, is that neutron di!raction allows the measurement of complete pole "gures of cylindrical samples. Second, is the sample preparation which consists only on cutting the wires and "xing on a sample holder. Third, is that corrections can be reduced to background correction that high accurate texture data are obtained. This high accuracy is necessary for the deter-
0921-4526/00/$ - see front matter 2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 1 - 4 5 2 6 ( 9 9 ) 0 1 5 4 0 - 9
Physb=16409=Jaya=VVC=BG H.-G. Brokmeier et al. / Physica B 276}278 (2000) 888}889
Fig. 1. Texture development of the Fe texture (ISEM34 * iterative series expansion method with lmax"34; simulation by the 2-site viscoplastic self-consistent model with spin sharing).
mination of small texture variations. Based on the high symmetry of the wire drawing process the texture is axial symmetric. Consequently, one-dimensional pole "gures were measured to save counting time. A rotating sample holder was used to increase the grain statistics. Six pole "gures for each sample and three pole "gures for each phase were detected * Fe (1 1 0), (2 0 0) and (2 1 1); Cu (1 1 1), (2 0 0), (2 2 0).
889
normalization of the pole "gure. The best correlation was obtained between the experimental results and the iterative series expansion method using lmax"34. A very good agreement was reached by the 2-site self-consistent model [3] taking into account that both phases share there spin during deformation, see Fig. 1. Other simulations based on Taylor models or on viscoplastic selfconsistent models are able to describe the texture type but not the sharpness of the texture. The Fe-texture goes down for soft strains from 5.6 to 5.1 mrad (Von Mises strain of 0.50). By increasing strain the texture develops sharper continuously up to a Von Mises strain of 2.5. The texture decrease at increasing strain can be explained by a curling of Fe and Cu particles [1]. The Cu texture is much weaker than the Fe texture. In the case of the starting material the 11 0 02 texture component is the strongest which is originated by recrystallization of the hot extrusion. These component goes down continuously by increasing deformation. The development of the weaker 11 1 12 component looks similar to the Fe texture. Soft strain leads to a texture decrease followed by an increase of the texture sharpness up to a Von Mises strain to 2.5. The curling a!ects on both phases, Cu and Fe, and consequently the texture becomes weaker.
Acknowledgements 3. Results The starting material for this investigation, a hot extruded rod, shows in the case of Fe a 11 1 02 "ber texture with an orientation density of about 5.6 mrd. In the case of copper a double "ber was formed (11 0 02 with 5.4 mrad and 11 1 12 with 2.2 mrad). The texture development of these typical texture types for Fe and Cu were correlated to the deformation. Quantitative texture calculation was performed by di!erent versions of the series expansion method, by di!erent versions of the WIMV method and by MENTEX. All programs give su$cient results. In the case of the Fe-texture the orientation density of the 11 1 02 "ber can be calculated directly by
This project was funded by the German}Argentine Intergovernmental Agreement No. ARG 6 L1A 1A/2 and CONICET-Argentina. Neutron di!raction was supported by the German Ministry for Research and Foundation (BMBF-03BR4CLA7).
References [1] R. Beuse et al., Scripta Met. 27 (1992) 767. [2] H.-G. Brokmeier et al., Mater Sci. Forum 273}275 (1998) 277. [3] R.E. Bolmaro et al., Comput. Mater. Sci. 9 (1997) 237.