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Aluminum-lithium alloy prepared by a solid-state route applying an alternative fast sintering route based on induction heating
Journal Pre-proofs Aluminum-Lithium alloy prepared by a solid-state route applying an alternative fast sintering route based on induction heating J.M. Mendoza-Duarte, M. Sagarnaga-Fernandez, E.G. Moreno-Resendiz, H.M. Medrano-Prieto, I. Estrada-Guel, C.G. Garay-Reyes, C. Carreño-Gallardo, R. Martínez-Sánchez PII: DOI: Reference:
S0167-577X(19)31810-5 https://doi.org/10.1016/j.matlet.2019.127178 MLBLUE 127178
To appear in:
Materials Letters
Received Date: Revised Date: Accepted Date:
2 December 2019 12 December 2019 13 December 2019
Please cite this article as: J.M. Mendoza-Duarte, M. Sagarnaga-Fernandez, E.G. Moreno-Resendiz, H.M. MedranoPrieto, I. Estrada-Guel, C.G. Garay-Reyes, C. Carreño-Gallardo, R. Martínez-Sánchez, Aluminum-Lithium alloy prepared by a solid-state route applying an alternative fast sintering route based on induction heating, Materials Letters (2019), doi: https://doi.org/10.1016/j.matlet.2019.127178
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
© 2019 Published by Elsevier B.V.
Aluminum-Lithium alloy prepared by a solid-state route applying an alternative fast sintering route based on induction heating
J.M. Mendoza-Duarte1, M. Sagarnaga-Fernandez2, E.G. Moreno-Resendiz2, H.M. MedranoPrieto1, I. Estrada-Guel1*, C.G. Garay-Reyes1, C. Carreño-Gallardo1 and R. Martínez-Sánchez1 1
Centro de Investigación en Materiales Avanzados, CIMAV, Miguel de Cervantes 120, Chihuahua, Chih. 31136, Mexico
2
Universidad Autonoma de Chihuahua, Facultad de Ingeniería, Circuito No. 1, Nuevo Campus Universitario, Chihuahua, Chih. 31240, Mexico
Abstract Al-Li alloys with different lithium contents were processed by mechanical alloying and sintered by an alternative route based on induction heating to keep the refined microstructure achieved by milling after sintering. The mechanical and microstructural features of samples sintered by a conventional route and fast induction heating were evaluated. Optical and TEM studies showed higher densification and better-refined microstructure retention after sintering using induction heating. Increased values of yield strength and hardness were obtained in the induction sintered alloys due to the porosity reduction complemented with finer microstructure.
Keywords: Intermetallic alloys and compounds; Metallurgy; Metals and alloys; Microstructure; Powder Technology; Sintering.
1. Introduction Technological evolution in the modern industry leads to the development of new materials designed to fulfill its requirements and processing routes to obtain them massively, cheaper, and
faster. A tangible example is the aluminum (Al) technologic journey; this metal was remained as an enigma for millennia, turn into precious metal, and became a universal material used in every sphere of human life. Even though Persians made their clay pottery containing aluminum oxide 7,000 years ago [1], it was not until 1845 that Friedrich Wöhler produced the first pure Al sample (only a few milligrams). Later, Henri Deville (1854) obtained the first Al commercial bars presented at the World Exhibition in 1855, being more expensive than gold. Deville recognized the vast technological potential of Al and understood that its future was not just to be associated with jewelry. Verne (1865) wrote about the fictitious attempt to send a man to the moon, and the chosen material was Al due to its "lightness and strength." Al was later used as an ornament in the Washington Monument, taking advantage of its high corrosion resistance. On the other hand, lithium (Li) is a soft, silvery metal highly reactive, being the lightest metal [2], when Li is added to Al (1%-Li); the alloy decreases its density by 3% and increasing elasticity modulus by 6% [3]–[7]. Thus, Al-Li alloys are particularly sought in the aerospace industry due to its exceptional strength-to-weight ratio [3]. Al-Li alloys have been produced mainly by three methods: ingot metallurgy [4], powder metallurgy (PM) [6], and splat quenching. Ingot metallurgy had issues related to the high reactivity of molten Al-Li with oxygen and humidity, forming foreign inclusions and increased explosion risks. Meanwhile, PM has the advantages of greater composition and microstructural flexibility [6]. Mechanical alloying (MA) is a solid-state route that has been extensively employed to produce nanocrystalline materials with increased properties as a result of severe plastic deformation [8]. This particular deformation in metals can lead to grain refinement at the submicron and nanometer scale. Additionally, to grain-refining, increased grain boundaries (GB) can improve solute atoms mobility, modifying the mechanical response of samples [9]. To obtain solid samples from MA´ed powders is necessary to sinter
them. Unfortunately, conventional sintering (using high temperature and longer holding time) induces material transfer mechanisms which practically destroyed the intrinsic properties and refined microstructure reached by MA. In this study, we demonstrate the potential and evident advantages of using an alternative route based on fast induction heating for sintering mechanically alloyed Al-Li powders increasing their mechanical performance.
2. Experimental procedure Some Al-Li alloys with different Li concentrations were prepared using MA. To produce solid samples for characterization, alloyed powders were processed using two routes: the conventional method (CM) and high-frequency induction sintering (HFIS).
2.1 Materials and methods 2.1.1 Powders preparation Pure Al powder (99.5%) and cast Al-5%Li master alloy chips were used as raw materials. To produce microstructurally refined samples, 8g of mixtures of Al with 0, 1, 2 and 4%Li were weighed and milled in a high-energy ball mill (Spex 8000M) for 2h in a hardened steel vial. To avoid agglomeration and to obtain a finer distribution of powder particle size, stearic acid was used as a process control agent.
2.1.2 Consolidation of samples Al-Li (0, 1, 2 and 4%) powders were compacted and sintered to obtain cylindrical forms (6x12mm, diameter and height) following two routes: Using CM the powders where introduced in a steel die and cold compacted using 900 MPa of uniaxial pressure; these “green” samples were put in a conventional furnace with argon atmosphere, using a heating slope of 10°C/min
until 550°C, held for 3h and cooling down inside the furnace. With HFIS, the compaction and sintering process was carried out at the same time. The powders were put in a steel die (Fig. 1) and compacted under 450MPa; after one minute, the high-frequency induction device (frequency of about 70kHz and 1.5kW) is turned on to heating the die with a slope of 135°C/min. The sintering temperature was 450°C (it was measured with a thermowell located near to sample) and it was held for 3 minutes. After sintering, the current was turned off, pressure released and the die cooled down using a forced flow of air. The sample was extracted after the die reached room temperature.
3. Materials characterization The morphological studies of milled powders were performed using a JEOL-JSM-7201F microscope and the microstructural constitution was observed using a TEM-Hitachi-7700. Phase identification and structural studies were done in a Bruker-D8 diffractometer using CuKα radiation. Li concentration was determined by inductively coupled plasma (ICP) in a ThermoScientific-6500 device. Consolidated samples were polished and micro-etched to reveal their microstructure to be studied through optical microscopy. Density was calculated, weighing the samples and divided them by their geometrical volume. The microhardness Vickers was obtained using a Leco-LM300AT micrometer (200g) and compressive testing was performed in an Instron-4468a machine at room temperature. The average and standard deviation from hardness and compression tests were reported. TEM samples were prepared by a focused ion beam technique.
3.1 Powders characterization
The used nomenclature is described in Table 1. After milling, the metallic particles increased their size due to micro-forging events forming bigger flake-like particles, A4L sample exhibited a broader size distribution with small satellites attached to the bigger ones. The ICP results (table 1) confirm that Li concentration remains in the powders after milling (Figs. 2a-2d). In Fig. 2e, the diffractograms of the alloyed powders shown peaks broadening due to crystallite size reduction, Al reflections are slightly shifted; indicating a lattice parameter changes as a consequence of Al-Li solid-solution formation. Table 1 shows the calculated lattice parameter values, where A2L and A4L samples present a slight variation [10,11], suggesting Li introduction in the Al structure. Contrary, the A1L sample showed no significant difference due to the small Li addition.
3.2 Consolidated samples characterization In Fig. 3 not only it is noticeable the refined microstructure obtained after milling (unsintered) and how this particular characteristic was kept after HFIS sintering, meanwhile by CM is almost eliminated. It was reported that small grains with a fine distribution of precipitates generated by GB wetting transitions are attractive routes to yield stress increase [12]. As can be seen in Fig. 3a, HFIS samples reached superior yield strength and hardness due to these features. Higher densification levels (Fig. 3b) were obtained by HFIS due to the simultaneous compaction and sintering that improved the diffusion events. The density reduction due to the Li addition observed in this work was also mentioned by some researches [3–7]. Low density found in A0L samples was obtained possibly due to particle size, connectivity and grain growth, which are critical to controlling porous microstructure [13], making difficult the compaction (Fig. 2a).
In TEM micrographs (Fig. 4), the grains of the CM sample grown due to a higher temperature and longer processing time (550°C-180 min). Sauvage et al., mentioned that high atomic mobility along GB is enhanced during deformation due to dislocation and vacancies rise, leading to wetting transitions and fast growth of precipitates located at triple junctions [I2]. In contrast, using HFIS, the refined and laminar microstructure was kept because of its reduced processing conditions (450°C-3min).
4. Conclusions Al-Li powders were produced using MA and sintered by HFIS, obtaining higher mechanical response compared to CM. XRD studies showed a solid solution formation of Li in Al, observing as a slight change of the Al lattice parameter. SEM and TEM evidence showed that HFIS samples presented better microstructural retention and higher densification after sintering (compared to CM), rising (270%) microhardness, and (160%) the yield strength. References [1] American Chemical Society, Production of Aluminum: The Hall-Héroult Process (1997) from https://www.acs.org. [2] L. A. Gil-Alana and M. Monge, Lithium: Production and estimated consumption. Evidence of persistence, Resour. Policy 60 (2017) 198–202. [3] M. J. Adinoyi, N. Merah, and J. Albinmousa, Shear fatigue behavior of AW2099-T83 aluminum-lithium alloy, Int. J. Fatigue 117 (2018) 101–110. [4] C. Meric, Physical and mechanical properties of cast under vacuum aluminum alloy 2024 containing lithium additions, Mater. Res. Bull. 35 (2000) 1479–1494. [5] J. L. T. Dorin, A. Vahid, Aluminium Lithium Alloys Chapter 11 in Fundamentals of Aluminium Metallurgy Recent Advances Edited by Roger N. Lumley Woodhead Publishing Series, 2018. [6] E. A. Starke, Historical Development and Present Status of Aluminum-Lithium Alloys
Chapter 1 in Aluminum-Lithium Alloy. Elsevier Inc., 2014. [7] J. Han, J. Wang, M. Zhang, and K. Niu, Susceptibility of lithium containing aluminum alloys to cracking during solidification, Materialia 5 (2019) 100203. [8] C. Suryanarayana, Mechanical alloying and milling, Prog. Mater. Sci. 46 (2001) 1–184. [9] Nguyen Q. Chinh, Ruslan Z. Valiev, Xavier Sauvage, et al., Grain Boundary Phenomena in an Ultrafine-Grained Al–Zn Alloy with Improved Mechanical Behavior for Micro-Devices, Adv. Eng. Mater. 16 (2014) 1000-1009. [10] X. Zhu, M. Schoenitz, and E. L. Dreizin, Mechanically alloyed Al-Li powders, J. Alloys Compd. 432 1-2 (2007) 111–115. [11] I.-J. S. Hwan-Cheol Kim, Dong-Ki Kim, Kee-Do Woo, In-Yong Ko, Consolidation of binderless WC–TiC by high frequency induction heating sintering, Int. J. Refract. Metals Hard Mater. 26 (2008) 48–54. [12] Xavier Sauvage, Maxim Yu. Murashkin, Boris B. Straumal, et al., Ultrafine Grained Structures Resulting from SPD-Induced Phase Transformation in Al–Zn Alloys, Adv. Eng. Mater. 17 (2015) 1821-1827. [13] K.-T. L. Jong-Yeol Yoo, In-Jin Shon, Byung-Hyun Choi, Fabrication and characterization of a Ni-YSZ anode support using high-frequency induction heated sintering (HFIHS), Ceram. Int. 37 (2011) 2569–2574.
Author Contribution Statement J.M. Mendoza-Duarte Methodology Validation, Visualization M. Sagarnaga-Fernandez Conceptualization, Data Curation, Visualization E.G. Moreno-Resendiz Conceptualization, Data Curation, Visualization H.M. Medrano-Prieto Software, I. Estrada-Guel Validation, Writing - Review & Editing C.G. Garay-Reyes Software, C. Carreño-Gallardo Investigation and R. Martínez-Sánchez Validation, Supervision
Declaration of interests ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. ☐The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:
Figure 1. Image of used HFIS array and die diagram.
Figure 2. SEM powders micrographs of a) A0L, b) A1L, c) A2L and d) A4L samples and e) alloys XRD patterns.
a)
b)
Figure 3.- Micrographs of unsintered and sintered samples prepared trough CM and HFIS. (a) Mechanical response and (b) densification of sintered samples.
a)
b)
Figure 4.- TEM micrographs of A2L sintered samples by a) CM and b) HFIS.
Table 1. Nomenclature, Li content and lattice parameter of milled powders. Sample
Abbreviation
Li% ICP
Lattice parameter (nm)
Al
AOL
0.0
0.4042
AI-1%Li
All
0.977
0.4046
AI-2%Li
A2L
1.992
0.4051
AI-4%Li
A4L
4.118
0.4051
Highlights:
Some Al-Li alloys were processed by mechanical alloying
Powder samples were sintered following two routes: HFIS and conventional
With HFIS the refined microstructure achieved by milling was kept
HFIS induced higher densification rates due porosity reduction
The above increased the mechanical response of samples
S0167-577X(19)31810-5 https://doi.org/10.1016/j.matlet.2019.127178 MLBLUE 127178
To appear in:
Materials Letters
Received Date: Revised Date: Accepted Date:
2 December 2019 12 December 2019 13 December 2019
Please cite this article as: J.M. Mendoza-Duarte, M. Sagarnaga-Fernandez, E.G. Moreno-Resendiz, H.M. MedranoPrieto, I. Estrada-Guel, C.G. Garay-Reyes, C. Carreño-Gallardo, R. Martínez-Sánchez, Aluminum-Lithium alloy prepared by a solid-state route applying an alternative fast sintering route based on induction heating, Materials Letters (2019), doi: https://doi.org/10.1016/j.matlet.2019.127178
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
© 2019 Published by Elsevier B.V.
Aluminum-Lithium alloy prepared by a solid-state route applying an alternative fast sintering route based on induction heating
J.M. Mendoza-Duarte1, M. Sagarnaga-Fernandez2, E.G. Moreno-Resendiz2, H.M. MedranoPrieto1, I. Estrada-Guel1*, C.G. Garay-Reyes1, C. Carreño-Gallardo1 and R. Martínez-Sánchez1 1
Centro de Investigación en Materiales Avanzados, CIMAV, Miguel de Cervantes 120, Chihuahua, Chih. 31136, Mexico
2
Universidad Autonoma de Chihuahua, Facultad de Ingeniería, Circuito No. 1, Nuevo Campus Universitario, Chihuahua, Chih. 31240, Mexico
Abstract Al-Li alloys with different lithium contents were processed by mechanical alloying and sintered by an alternative route based on induction heating to keep the refined microstructure achieved by milling after sintering. The mechanical and microstructural features of samples sintered by a conventional route and fast induction heating were evaluated. Optical and TEM studies showed higher densification and better-refined microstructure retention after sintering using induction heating. Increased values of yield strength and hardness were obtained in the induction sintered alloys due to the porosity reduction complemented with finer microstructure.
Keywords: Intermetallic alloys and compounds; Metallurgy; Metals and alloys; Microstructure; Powder Technology; Sintering.
1. Introduction Technological evolution in the modern industry leads to the development of new materials designed to fulfill its requirements and processing routes to obtain them massively, cheaper, and
faster. A tangible example is the aluminum (Al) technologic journey; this metal was remained as an enigma for millennia, turn into precious metal, and became a universal material used in every sphere of human life. Even though Persians made their clay pottery containing aluminum oxide 7,000 years ago [1], it was not until 1845 that Friedrich Wöhler produced the first pure Al sample (only a few milligrams). Later, Henri Deville (1854) obtained the first Al commercial bars presented at the World Exhibition in 1855, being more expensive than gold. Deville recognized the vast technological potential of Al and understood that its future was not just to be associated with jewelry. Verne (1865) wrote about the fictitious attempt to send a man to the moon, and the chosen material was Al due to its "lightness and strength." Al was later used as an ornament in the Washington Monument, taking advantage of its high corrosion resistance. On the other hand, lithium (Li) is a soft, silvery metal highly reactive, being the lightest metal [2], when Li is added to Al (1%-Li); the alloy decreases its density by 3% and increasing elasticity modulus by 6% [3]–[7]. Thus, Al-Li alloys are particularly sought in the aerospace industry due to its exceptional strength-to-weight ratio [3]. Al-Li alloys have been produced mainly by three methods: ingot metallurgy [4], powder metallurgy (PM) [6], and splat quenching. Ingot metallurgy had issues related to the high reactivity of molten Al-Li with oxygen and humidity, forming foreign inclusions and increased explosion risks. Meanwhile, PM has the advantages of greater composition and microstructural flexibility [6]. Mechanical alloying (MA) is a solid-state route that has been extensively employed to produce nanocrystalline materials with increased properties as a result of severe plastic deformation [8]. This particular deformation in metals can lead to grain refinement at the submicron and nanometer scale. Additionally, to grain-refining, increased grain boundaries (GB) can improve solute atoms mobility, modifying the mechanical response of samples [9]. To obtain solid samples from MA´ed powders is necessary to sinter
them. Unfortunately, conventional sintering (using high temperature and longer holding time) induces material transfer mechanisms which practically destroyed the intrinsic properties and refined microstructure reached by MA. In this study, we demonstrate the potential and evident advantages of using an alternative route based on fast induction heating for sintering mechanically alloyed Al-Li powders increasing their mechanical performance.
2. Experimental procedure Some Al-Li alloys with different Li concentrations were prepared using MA. To produce solid samples for characterization, alloyed powders were processed using two routes: the conventional method (CM) and high-frequency induction sintering (HFIS).
2.1 Materials and methods 2.1.1 Powders preparation Pure Al powder (99.5%) and cast Al-5%Li master alloy chips were used as raw materials. To produce microstructurally refined samples, 8g of mixtures of Al with 0, 1, 2 and 4%Li were weighed and milled in a high-energy ball mill (Spex 8000M) for 2h in a hardened steel vial. To avoid agglomeration and to obtain a finer distribution of powder particle size, stearic acid was used as a process control agent.
2.1.2 Consolidation of samples Al-Li (0, 1, 2 and 4%) powders were compacted and sintered to obtain cylindrical forms (6x12mm, diameter and height) following two routes: Using CM the powders where introduced in a steel die and cold compacted using 900 MPa of uniaxial pressure; these “green” samples were put in a conventional furnace with argon atmosphere, using a heating slope of 10°C/min
until 550°C, held for 3h and cooling down inside the furnace. With HFIS, the compaction and sintering process was carried out at the same time. The powders were put in a steel die (Fig. 1) and compacted under 450MPa; after one minute, the high-frequency induction device (frequency of about 70kHz and 1.5kW) is turned on to heating the die with a slope of 135°C/min. The sintering temperature was 450°C (it was measured with a thermowell located near to sample) and it was held for 3 minutes. After sintering, the current was turned off, pressure released and the die cooled down using a forced flow of air. The sample was extracted after the die reached room temperature.
3. Materials characterization The morphological studies of milled powders were performed using a JEOL-JSM-7201F microscope and the microstructural constitution was observed using a TEM-Hitachi-7700. Phase identification and structural studies were done in a Bruker-D8 diffractometer using CuKα radiation. Li concentration was determined by inductively coupled plasma (ICP) in a ThermoScientific-6500 device. Consolidated samples were polished and micro-etched to reveal their microstructure to be studied through optical microscopy. Density was calculated, weighing the samples and divided them by their geometrical volume. The microhardness Vickers was obtained using a Leco-LM300AT micrometer (200g) and compressive testing was performed in an Instron-4468a machine at room temperature. The average and standard deviation from hardness and compression tests were reported. TEM samples were prepared by a focused ion beam technique.
3.1 Powders characterization
The used nomenclature is described in Table 1. After milling, the metallic particles increased their size due to micro-forging events forming bigger flake-like particles, A4L sample exhibited a broader size distribution with small satellites attached to the bigger ones. The ICP results (table 1) confirm that Li concentration remains in the powders after milling (Figs. 2a-2d). In Fig. 2e, the diffractograms of the alloyed powders shown peaks broadening due to crystallite size reduction, Al reflections are slightly shifted; indicating a lattice parameter changes as a consequence of Al-Li solid-solution formation. Table 1 shows the calculated lattice parameter values, where A2L and A4L samples present a slight variation [10,11], suggesting Li introduction in the Al structure. Contrary, the A1L sample showed no significant difference due to the small Li addition.
3.2 Consolidated samples characterization In Fig. 3 not only it is noticeable the refined microstructure obtained after milling (unsintered) and how this particular characteristic was kept after HFIS sintering, meanwhile by CM is almost eliminated. It was reported that small grains with a fine distribution of precipitates generated by GB wetting transitions are attractive routes to yield stress increase [12]. As can be seen in Fig. 3a, HFIS samples reached superior yield strength and hardness due to these features. Higher densification levels (Fig. 3b) were obtained by HFIS due to the simultaneous compaction and sintering that improved the diffusion events. The density reduction due to the Li addition observed in this work was also mentioned by some researches [3–7]. Low density found in A0L samples was obtained possibly due to particle size, connectivity and grain growth, which are critical to controlling porous microstructure [13], making difficult the compaction (Fig. 2a).
In TEM micrographs (Fig. 4), the grains of the CM sample grown due to a higher temperature and longer processing time (550°C-180 min). Sauvage et al., mentioned that high atomic mobility along GB is enhanced during deformation due to dislocation and vacancies rise, leading to wetting transitions and fast growth of precipitates located at triple junctions [I2]. In contrast, using HFIS, the refined and laminar microstructure was kept because of its reduced processing conditions (450°C-3min).
4. Conclusions Al-Li powders were produced using MA and sintered by HFIS, obtaining higher mechanical response compared to CM. XRD studies showed a solid solution formation of Li in Al, observing as a slight change of the Al lattice parameter. SEM and TEM evidence showed that HFIS samples presented better microstructural retention and higher densification after sintering (compared to CM), rising (270%) microhardness, and (160%) the yield strength. References [1] American Chemical Society, Production of Aluminum: The Hall-Héroult Process (1997) from https://www.acs.org. [2] L. A. Gil-Alana and M. Monge, Lithium: Production and estimated consumption. Evidence of persistence, Resour. Policy 60 (2017) 198–202. [3] M. J. Adinoyi, N. Merah, and J. Albinmousa, Shear fatigue behavior of AW2099-T83 aluminum-lithium alloy, Int. J. Fatigue 117 (2018) 101–110. [4] C. Meric, Physical and mechanical properties of cast under vacuum aluminum alloy 2024 containing lithium additions, Mater. Res. Bull. 35 (2000) 1479–1494. [5] J. L. T. Dorin, A. Vahid, Aluminium Lithium Alloys Chapter 11 in Fundamentals of Aluminium Metallurgy Recent Advances Edited by Roger N. Lumley Woodhead Publishing Series, 2018. [6] E. A. Starke, Historical Development and Present Status of Aluminum-Lithium Alloys
Chapter 1 in Aluminum-Lithium Alloy. Elsevier Inc., 2014. [7] J. Han, J. Wang, M. Zhang, and K. Niu, Susceptibility of lithium containing aluminum alloys to cracking during solidification, Materialia 5 (2019) 100203. [8] C. Suryanarayana, Mechanical alloying and milling, Prog. Mater. Sci. 46 (2001) 1–184. [9] Nguyen Q. Chinh, Ruslan Z. Valiev, Xavier Sauvage, et al., Grain Boundary Phenomena in an Ultrafine-Grained Al–Zn Alloy with Improved Mechanical Behavior for Micro-Devices, Adv. Eng. Mater. 16 (2014) 1000-1009. [10] X. Zhu, M. Schoenitz, and E. L. Dreizin, Mechanically alloyed Al-Li powders, J. Alloys Compd. 432 1-2 (2007) 111–115. [11] I.-J. S. Hwan-Cheol Kim, Dong-Ki Kim, Kee-Do Woo, In-Yong Ko, Consolidation of binderless WC–TiC by high frequency induction heating sintering, Int. J. Refract. Metals Hard Mater. 26 (2008) 48–54. [12] Xavier Sauvage, Maxim Yu. Murashkin, Boris B. Straumal, et al., Ultrafine Grained Structures Resulting from SPD-Induced Phase Transformation in Al–Zn Alloys, Adv. Eng. Mater. 17 (2015) 1821-1827. [13] K.-T. L. Jong-Yeol Yoo, In-Jin Shon, Byung-Hyun Choi, Fabrication and characterization of a Ni-YSZ anode support using high-frequency induction heated sintering (HFIHS), Ceram. Int. 37 (2011) 2569–2574.
Author Contribution Statement J.M. Mendoza-Duarte Methodology Validation, Visualization M. Sagarnaga-Fernandez Conceptualization, Data Curation, Visualization E.G. Moreno-Resendiz Conceptualization, Data Curation, Visualization H.M. Medrano-Prieto Software, I. Estrada-Guel Validation, Writing - Review & Editing C.G. Garay-Reyes Software, C. Carreño-Gallardo Investigation and R. Martínez-Sánchez Validation, Supervision
Declaration of interests ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. ☐The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:
Figure 1. Image of used HFIS array and die diagram.
Figure 2. SEM powders micrographs of a) A0L, b) A1L, c) A2L and d) A4L samples and e) alloys XRD patterns.
a)
b)
Figure 3.- Micrographs of unsintered and sintered samples prepared trough CM and HFIS. (a) Mechanical response and (b) densification of sintered samples.
a)
b)
Figure 4.- TEM micrographs of A2L sintered samples by a) CM and b) HFIS.
Table 1. Nomenclature, Li content and lattice parameter of milled powders. Sample
Abbreviation
Li% ICP
Lattice parameter (nm)
Al
AOL
0.0
0.4042
AI-1%Li
All
0.977
0.4046
AI-2%Li
A2L
1.992
0.4051
AI-4%Li
A4L
4.118
0.4051
Highlights:
Some Al-Li alloys were processed by mechanical alloying
Powder samples were sintered following two routes: HFIS and conventional
With HFIS the refined microstructure achieved by milling was kept
HFIS induced higher densification rates due porosity reduction
The above increased the mechanical response of samples