The Experts below are selected from a list of 82164 Experts worldwide ranked by ideXlab platform
S. Ramanathan - One of the best experts on this subject based on the ideXlab platform.
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Development of Processing Map for 7075 Al/20% SiCp Composite
Journal of Materials Engineering and Performance, 2011Co-Authors: M. Rajamuthamilselvan, S. RamanathanAbstract:The hot deformation behavior and microstructure evolution of 7075 Al/20% SiCp composite have been studied using the Processing Map. Compression tests were carried out in the temperature range of 300-500 °C and at the strain rate range of 0.001-1.0 s−1. The stable and unstable regions in the Map were verified with the microstructural observations of the deformed compression specimens. The “stable” regions, i.e., dynamic recrystallization and “unstable” regions such as debonding of SiC particles, matrix crack, and adiabatic shear band formation were identified from the Processing Map and compared with the reported microstructural observations of the deformed compression specimens. The optimum hot working conditions for this composite were identified.
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Hot deformation and Processing Maps of extruded ZE41A magnesium alloy
Materials & Design (1980-2015), 2010Co-Authors: S. Anbuselvan, S. RamanathanAbstract:Abstract The hot deformation behavior and microstructure evolution of extruded ZE41A magnesium alloy has been studied using the Processing Map. The compression tests were conducted in the temperature range of 250–450 °C and the strain rate range of 0.001–1.0 s −1 to establish the Processing Map. The dynamic recrystallization (DRX) and instability zones were identified and validated through micrographs. The observations were performed in order to describe the behavior of the material under hot forming operation in terms of material damage and micro-structural modification.
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Processing Map for hot working of SiCp/7075 Al composites
Transactions of Nonferrous Metals Society of China, 2010Co-Authors: M. Rajamuthamilselvan, S. Ramanathan, R. KarthikeyanAbstract:Abstract The hot deformation behaviour of 7075 aluminium alloy reinforced with 10% of SiC particles was studied by employing both “Processing Maps” and microstructural observations. The composite was characterized by employing optical microscope to evaluate the microstructural transformations and instability phenomena. The material investigated was deformed by compression in the temperature and strain rate ranges of 300–500 °C and 0.001–1.0 s −1 , respectively. The deformation efficiency was calculated by strain rate sensitivity ( m ) values obtained by hot compression tests. The power dissipation efficiency and instability parameters were evaluated and Processing Maps were constructed for strain of 0.5. The optimum domains and instability zone were obtained for the composites. The optimum Processing conditions are obtained in the strain rate range of 0.1–0.9 s −1 and temperature range of 390–440 °C with the efficiency of 30%.
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Development of Processing Maps for as-cast ZE41A magnesium alloy
Transactions of Nonferrous Metals Society of China, 2010Co-Authors: S. Anbu Selvan, S. Ramanathan, R. Karthikeyan, B.k. RaghunathAbstract:The hot deformation behavior of as-cast ZE41A magnesium alloy was studied by employing both Processing Maps and microstructural observations. To obtain Processing Map, hot compression tests were performed over a range of strain rates (0.001−1.0 s −1 ) and temperatures (250−450 ℃). Power dissipation efficiency (η) and instability parameter )) ( ( e ξ & were evaluated and Processing Maps were developed for the strain of 0.5. The dynamic recrystallization (DRX) and instable zones were identified and validated through micrographs. The Processing Maps can be used to select optimum strain rates and temperatures for effective hot
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Development of Processing Maps for Al/SiCp composite using fuzzy logic
Journal of Materials Processing Technology, 2007Co-Authors: S. Ramanathan, R. Karthikeyan, Manoj GuptaAbstract:Abstract In the present study the aluminium reinforced with 10% SiCp particulate composites were produced through powder metallurgy route and Processing Map was developed. The composite specimens were subjected to compression test at different strains, strain rates and temperatures. Using the load-stroke data, flow stress–strain were evaluated. Fuzzy logic has been implemented for the prediction of flow stress. Power dissipation efficiency and instability parameter were evaluated and plotted with temperature and stain rate using the predicted values of flow stress from fuzzy logic. The contour plots were superimposed to obtain the Processing Maps. The dynamic recrystallisation zones and instable zones were identified and validated through micrographs. The Processing Maps can be used to select optimum strain rates and temperatures for effective hot working of Al/10% SiC composites.
Guanjun Qiao - One of the best experts on this subject based on the ideXlab platform.
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Hot deformation and optimization of process parameters of an as-cast 6Mo superaustenitic stainless steel: A study with Processing Map
Materials & Design, 2014Co-Authors: Guiwu Liu, Ying Han, Dening Zou, Jiapeng Sun, Zhongqi Shi, Guanjun QiaoAbstract:Abstract The deformation characteristics of as-cast S31254 superaustenitic stainless steel (SASS) have been investigated by the isothermal compression testing at temperature of 1173–1473 K and strain rate of 0.01–10 s−1 on a Gleeble-1500D thermo-mechanical simulator. The approach of Processing Map (PM) was used to reveal the hot workability affected by the process parameters (such as e , T and e) and microstructural evolution during the hot deformation. It is found that the process parameters have obvious effects on the power dissipation efficiency, instability factor and softening characteristic. The safe deformation domain can be identified from the PM, and the variation of peak efficiency with strain is obtained in the safe domain. The optimal hot working condition at large strains (⩾0.7) corresponds to the temperature range of 1376–1473 K and the intermediate strain rate range of 0.07–1.38 s−1, with a peak efficiency of 35% at ∼1473 K and 0.4 s−1. In this field, the original coarse grains can be substituted by the fine recrystallized grains, indicating that the high power is dissipated by the dynamic recrystallization. Meanwhile, three instable regions, which should be avoided in hot Processing, are detected from the PM and the related instability mechanisms are also discussed.
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investigation on hot deformation of 20cr 25ni superaustenitic stainless steel with starting columnar dendritic microstructure based on kinetic analysis and Processing Map
Materials Science and Technology, 2013Co-Authors: Ying Han, Dening Zou, G. Liu, Jiapeng Sun, Guanjun QiaoAbstract:AbstractThe deformation behaviour of a 20Cr–25Ni superaustenitic stainless steel (SASS) with initial microstructure of columnar dendrites was investigated using the hot compression method at temperatures of 1000–1200°C and strain rates of 0·01–10 s−1. It was found that the flow stress was strongly dependent on the applied temperature and strain rate. The constitutive equation relating to the flow stress, temperature and stain rate was proposed for hot deformation of this material, and the apparent activation energy of deformation was calculated to be 516·7 kJ mol−1. Based on the dynamic materials model and the Murty’s instability criterion, the variations of dissipation efficiency and instability factor with Processing parameters were studied. The Processing Map, combined with the instability Map and the dissipation Map, was constructed to demonstrate the relationship between hot workability and microstructural evolution. The stability region for hot Processing was inferred accurately from the Map. The op...
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Investigation on hot deformation of 20Cr–25Ni superaustenitic stainless steel with starting columnar dendritic microstructure based on kinetic analysis and Processing Map
Materials Science and Technology, 2013Co-Authors: Ying Han, Dening Zou, G. Liu, Jiapeng Sun, Guanjun QiaoAbstract:AbstractThe deformation behaviour of a 20Cr–25Ni superaustenitic stainless steel (SASS) with initial microstructure of columnar dendrites was investigated using the hot compression method at temperatures of 1000–1200°C and strain rates of 0·01–10 s−1. It was found that the flow stress was strongly dependent on the applied temperature and strain rate. The constitutive equation relating to the flow stress, temperature and stain rate was proposed for hot deformation of this material, and the apparent activation energy of deformation was calculated to be 516·7 kJ mol−1. Based on the dynamic materials model and the Murty’s instability criterion, the variations of dissipation efficiency and instability factor with Processing parameters were studied. The Processing Map, combined with the instability Map and the dissipation Map, was constructed to demonstrate the relationship between hot workability and microstructural evolution. The stability region for hot Processing was inferred accurately from the Map. The op...
Y. V. R. K. Prasad - One of the best experts on this subject based on the ideXlab platform.
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hot working behavior and Processing Map of a γ tial alloy synthesized by powder metallurgy
Materials & Design, 2011Co-Authors: K P Rao, Y. V. R. K. Prasad, K SureshAbstract:Abstract Powder metallurgy technique has been explored to synthesize a titanium aluminide alloy with the composition 46Ti–46Al–4Nb–2Cr–2Mn by mixing of elemental powders followed by hot isostatic pressing (HIP). The microstructure of the compact revealed the formation TiAl solid solution in addition to a Nb-rich phase. Cylindrical specimens from the HIP’ed billets were compressed at temperatures and strain rates in the ranges of 850–1050 °C and 0.0001–10 s −1 . A Processing Map has been developed on the basis of flow stress data at different temperatures and strain rates, which revealed that the alloy may be hot worked in the range 925–1050 °C and 0.0001–0.01 s −1 . Kinetic analysis of the flow stress data yielded a stress exponent of 4.4 and apparent activation energy of 387 kJ/mole which is close to that for self-diffusion of Al in γ TiAl.
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hot deformation behaviour of mg 3al alloy a study using Processing Map
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: N. Srinivasan, Y. V. R. K. Prasad, Rama P RaoAbstract:Abstract The hot deformation behaviour of Mg–3Al alloy has been studied using the Processing-Map technique. Compression tests were conducted in the temperature range 250–550 °C and strain rate range 3 × 10 −4 to 10 2 s −1 and the flow stress data obtained from the tests were used to develop the Processing Map. The various domains in the Map corresponding to different dissipative characteristics have been identified as follows: (i) grain boundary sliding (GBS) domain accommodated by slip controlled by grain boundary diffusion at slow strain-rates ( −3 s −1 ) in the temperature range from 350 to 450 °C, (ii) two different dynamic recrystallization (DRX) domains with a peak efficiency of 42% at 550 °C/10 −1 s −1 and 425 °C/10 2 s −1 governed by stress-assisted cross-slip and thermally activated climb as the respective rate controlling mechanisms and (iii) dynamic recovery (DRV) domain below 300 °C in the intermediate strain rate range from 3 × 10 −2 to 3 × 10 −1 s −1 . The regimes of flow instability have also been delineated in the Processing Map using an instability criterion. Adiabatic shear banding at higher strain rates (>10 1 s −1 ) and solute drag by substitutional Al atoms at intermediate strain rates (3 × 10 −2 to 3 × 10 −1 s −1 ) in the temperature range (350–450 °C) are responsible for flow instability. The relevance of these mechanisms with reference to hot working practice of the material has been indicated. The Processing Maps of Mg–3Al alloy and as-cast Mg have been compared qualitatively to elucidate the effect of alloying with aluminum on the deformation behaviour of magnesium.
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hot deformation behaviour of as cast mg 2zn 1mn alloy in compression a study with Processing Map
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2003Co-Authors: O Sivakesavam, Y. V. R. K. PrasadAbstract:The deformation behaviour of as-cast Mg-2Zn-1Mn alloy in the temperature range 300-500 degreesC and in the strain rate range 0.001-100 s(-1) has been studied using Processing Maps. For obtaining the Processing Map, the variation of the efficiency of power dissipation given by [2ml(m+1)] where 'm' is the strain rate sensitivity, is plotted as a function of temperature and strain rate. The Map exhibited a domain of dynamic recrystallization (DRX) occurring at 450 degreesC and 0.1 s(-1) which are the optimum parameters for hot working of the alloy. The material exhibits grain boundary cracking domain with a higher efficiency at temperatures higher than 450 degreesC and at lower strain rates. At strain rates higher than 3 s-1, the material undergoes flow localization which has to be avoided in mechanical Processing for obtaining consistent properties.
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characteristics of superplasticity domain in the Processing Map for hot working of as cast mg 11 5li 1 5al alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2002Co-Authors: O Sivakesavam, Y. V. R. K. PrasadAbstract:Processing Map for hot working of as-cast Mg-11.5Li-1.5Al alloy has been developed in the temperature range 200 450degreesC and strain rate range 0.001-100 s(-1). The Map exhibited a single domain with a peak efficiency of 65% occurring at 400degreesC and 0.001 s(-1). Under these conditions, the material exhibited abnormal elongation. On the basis of the elongation, the grain structure, the apparent activation energy for hot deformation (95 kJ mole (1)) and the peak efficiency of power dissipation (65% corresponding to a strain rate sensitivity of about 0.5), the domain is interpreted to represent superplasticity, At strain rates higher than about 10 s(-1), the material exhibits microstructural instability, while at temperatures of 450degreesC and it strain rate of 0.001 s (1), grain boundary cracking is observed.
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Superplasticity in β-zirconium: A study using a Processing Map
Scripta Metallurgica et Materialia, 1992Co-Authors: J.k. Chakravartty, S. Banerjee, Y. V. R. K. PrasadAbstract:The HCP {Alpha}-zirconium undergoes dynamic recrystallization (DRX) under hotworking conditions and the Processing Map for {alpha}-zirconium has revealed that the optimum conditions for DRX are 800{degrees} C and 0.1s{sup {minus}1}. The aim of this paper is to study the constitutive flow behavior of {beta}-zirconium at elevated temperatures in a wide range of strain rates. In view of the BCC crystal structure of {beta}-zirconium, the diffusivity is higher than in the {alpha}-phase and this will have a significant effect on the hot deformation characteristics. These are best studied using the approach of a Processing Map which represents the power dissipation efficiency with respect to an ideal linear dissipator, as a function of the applied strain rate and temperature. The Maps are interpreted on the basis of the Dynamic Materials Model.
Ying Han - One of the best experts on this subject based on the ideXlab platform.
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Hot deformation and optimization of process parameters of an as-cast 6Mo superaustenitic stainless steel: A study with Processing Map
Materials & Design, 2014Co-Authors: Guiwu Liu, Ying Han, Dening Zou, Jiapeng Sun, Zhongqi Shi, Guanjun QiaoAbstract:Abstract The deformation characteristics of as-cast S31254 superaustenitic stainless steel (SASS) have been investigated by the isothermal compression testing at temperature of 1173–1473 K and strain rate of 0.01–10 s−1 on a Gleeble-1500D thermo-mechanical simulator. The approach of Processing Map (PM) was used to reveal the hot workability affected by the process parameters (such as e , T and e) and microstructural evolution during the hot deformation. It is found that the process parameters have obvious effects on the power dissipation efficiency, instability factor and softening characteristic. The safe deformation domain can be identified from the PM, and the variation of peak efficiency with strain is obtained in the safe domain. The optimal hot working condition at large strains (⩾0.7) corresponds to the temperature range of 1376–1473 K and the intermediate strain rate range of 0.07–1.38 s−1, with a peak efficiency of 35% at ∼1473 K and 0.4 s−1. In this field, the original coarse grains can be substituted by the fine recrystallized grains, indicating that the high power is dissipated by the dynamic recrystallization. Meanwhile, three instable regions, which should be avoided in hot Processing, are detected from the PM and the related instability mechanisms are also discussed.
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investigation on hot deformation of 20cr 25ni superaustenitic stainless steel with starting columnar dendritic microstructure based on kinetic analysis and Processing Map
Materials Science and Technology, 2013Co-Authors: Ying Han, Dening Zou, G. Liu, Jiapeng Sun, Guanjun QiaoAbstract:AbstractThe deformation behaviour of a 20Cr–25Ni superaustenitic stainless steel (SASS) with initial microstructure of columnar dendrites was investigated using the hot compression method at temperatures of 1000–1200°C and strain rates of 0·01–10 s−1. It was found that the flow stress was strongly dependent on the applied temperature and strain rate. The constitutive equation relating to the flow stress, temperature and stain rate was proposed for hot deformation of this material, and the apparent activation energy of deformation was calculated to be 516·7 kJ mol−1. Based on the dynamic materials model and the Murty’s instability criterion, the variations of dissipation efficiency and instability factor with Processing parameters were studied. The Processing Map, combined with the instability Map and the dissipation Map, was constructed to demonstrate the relationship between hot workability and microstructural evolution. The stability region for hot Processing was inferred accurately from the Map. The op...
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Investigation on hot deformation of 20Cr–25Ni superaustenitic stainless steel with starting columnar dendritic microstructure based on kinetic analysis and Processing Map
Materials Science and Technology, 2013Co-Authors: Ying Han, Dening Zou, G. Liu, Jiapeng Sun, Guanjun QiaoAbstract:AbstractThe deformation behaviour of a 20Cr–25Ni superaustenitic stainless steel (SASS) with initial microstructure of columnar dendrites was investigated using the hot compression method at temperatures of 1000–1200°C and strain rates of 0·01–10 s−1. It was found that the flow stress was strongly dependent on the applied temperature and strain rate. The constitutive equation relating to the flow stress, temperature and stain rate was proposed for hot deformation of this material, and the apparent activation energy of deformation was calculated to be 516·7 kJ mol−1. Based on the dynamic materials model and the Murty’s instability criterion, the variations of dissipation efficiency and instability factor with Processing parameters were studied. The Processing Map, combined with the instability Map and the dissipation Map, was constructed to demonstrate the relationship between hot workability and microstructural evolution. The stability region for hot Processing was inferred accurately from the Map. The op...
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Investigation on hot deformation behavior of 00Cr23Ni4N duplex stainless steel under medium–high strain rates
Materials Characterization, 2011Co-Authors: Ying Han, Dening Zou, Zhiyu Chen, Guangwei Fan, Wei ZhangAbstract:Abstract The hot deformation behavior of 00Cr23Ni4N duplex stainless steel under medium–high strain rates (5–50 s − 1 ) has been analyzed using the Zener–Hollomon parameter and Processing Maps, which is based on compression tests made at temperatures ranging from 900 to 1150 °C. The results display the significant influence of high strain rate and high temperature on hot deformation behavior of 00Cr23Ni4N duplex stainless steel. A classical hyperbolic sine equation is applied to reveal the relations between the peak stress, strain rate and deformation temperature, in which the activation energy, Q and stress exponent, n are 263.4 kJ/mol and 2.6, respectively. The Zener–Hollomon parameters at low and high temperatures are calculated respectively to reflect the microstructural evolutions. Based on the Processing Map obtained, an ideal hot working condition for commercial Processing is in the temperature range between 1075 and 1150 °C with a strain rate of 10 to 30 s − 1 . Under such condition, both ferrite and austenite dynamic re-crystallizations can be obtained and the corresponding Zener–Hollomon parameter is relatively low. Furthermore, the unstable domains are indicated by the Processing Map.
Hai Tao Zhou - One of the best experts on this subject based on the ideXlab platform.
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Hot Deformation Characteristics of GH625 and Development of a Processing Map
Journal of Materials Engineering and Performance, 2013Co-Authors: Hai Tao Zhou, Ruo-mei Liu, Zhiyi Liu, Xin-ming Zhou, Q.z. Peng, F.h. Zhong, Yong PengAbstract:The hot deformation behavior of GH625 is investigated by a compression test in the temperature range of 950-1150 °C and the strain rate of 10−3-5 s−1. It is found that the flow stress behavior is described by the hyperbolic sine constitutive equation with average activation energy of 421 kJ/mol. Through the flow stresses’ curves, the Processing Maps are constructed and analyzed according to the dynamic materials model. In the Processing Map, the variation of the efficiency of the power dissipation is plotted as a function of temperature and strain rate, and the Maps exhibit a significant feature with a domain of dynamic recrystallization occurring at the temperature range of 950-1150 °C and in the strain rate range of 0.005-0.13 s−1, which are the optimum parameters for hot working of the alloy. Meanwhile, the instability zones of flow behavior can also be recognized by the Maps.
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Hot deformation behavior and Processing Maps for coiled tubing steel
Materials Science and Engineering: A, 2013Co-Authors: Zhen Dong Zhang, Hai Tao Zhou, Xianghua Liu, Dong Jie, Bingyu Zhang, Song YueAbstract:Abstract Hot compression test of coiled tubing steel is performed on Gleeble3500 at 850–1100 °C and strain rate from 0.001 s−1 to 5 s−1. It is found that the flow stress behavior is described by the hyperbolic sine constitutive equation in which the average activation energy of 390 kJ/mol is calculated. And the hot deformation behavior of coiled tubing steel is characterized by using Processing Maps developed on the basis of the dynamic materials model. The Processing Map shows the flow instable region and the flow stable region. The dynamic recovery (DRV) and dynamic recrystallization (DRX) occur in the stable region. In the Processing Map, the variation of the efficiency of the power dissipation is plotted as a function of temperature and strain rate. According to the Processing Map, the coiled tubing steel is rolled by the Thermo-Mechanical-Control-Process (TMCP), and finally it is obtained that the yield strength and tensile strength of coiled tubing steel are 565 MPa and 685 MPa respectively, and the elongation percentage is 32.1%.
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Development of Processing Maps for Coiled Tubing Steel
Advanced Materials Research, 2011Co-Authors: Zhen Dong Zhang, Hai Tao Zhou, Si Jun Li, Jie Dong, Xiao ZhouAbstract:Hot compression test of coiled tubing steel is performed on Gleeble3500 at 1123K—1373K and strain rate from 0.001 to 5s-1. The hot deformation behavior of coiled tubing steel was characterized using Processing Map developed on the basis of the dynamic materials model. The Processing Map gives the flow instable region and the flow stable region in which the process of dynamic recovery (DRV) and the dynamic recrystallization (DRX) occur. In the Processing Map, the variation of the efficiency of the power dissipation is plotted as a function of temperature and the strain rate. According to the Processing Map, the coiled tubing steel is rolled by The Thermo-Mechanical-Control-Process (TMCP), and finally it is obtained that the yield strength and tensile strength of coiled tubing steel are 565MPa and 685MPa respectively, and the elongation percentage is 32.1%.
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hot workability characteristics of magnesium alloy az80 a study using Processing Map
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Hai Tao Zhou, Ziqian Zhao, Zhaoyang Liu, S F Wen, Q D WangAbstract:Abstract The deformation behavior of as-cast AZ80 alloy is investigated by compression test with gleeble-1500 thermal simulator. The tests are performed in the temperature range of 200–500 °C and the strain rate of 0.001–20 s −1 . It is found that the flow stress behavior is described by the hyperbolic sine constitutive equation in which the average activation energy of 154.6 kJ/mol is calculated. Through the flow stresses behavior, the Processing Maps are calculated and analyzed according to the dynamic materials model. In the Processing Map the variation of the efficiency of the power dissipation is plotted as a function of temperature and strain rate. The Maps exhibit a domain of dynamic recrystallization (DRX) occurring at the temperature range of 420–500 °C and in the strain rate range of 10 −3 s −1 to 10 −2 s −1 which are the optimum parameters for hot working of the alloy. The instability zones of flow behavior can also be recognized by the Maps.