- Email: [email protected]
Features of the Al90Y10 alloy structure during solidification under high pressure
Journal of Crystal Growth 524 (2019) 125164
Contents lists available at ScienceDirect
Journal of Crystal Growth journal homepage: www.elsevier.com/locate/jcrysgro
Features of the Al90Y10 alloy structure during solidification under high pressure
T
S.G. Menshikovaa, , V.V. Brazhkinb, V.I. Lad'yanova, B.E. Pushkareva ⁎
a b
Udmurt Federal Research Center, Ural Branch, Russian Academy of Sciences, T. Baramzina Str., 34, 426067 Izhevsk, Russia L.F. Vereshagin Institute of High Pressure Physics, Russian Academy of Sciences, Kaluga Highway, 14, 108840 Moscow, Russia
ARTICLE INFO
ABSTRACT
Communicated by P.G. Peter Galenko
Using the methods of durametry, X-ray structural analysis, optical and electronic microscopy, we have compared the structures of the Al90Y10 hypereutectic alloy (hereinafter at.% is given) obtained at the atmospheric pressure and that produced with quick cooling under pressure of 9 GPa. It has been demonstrated that, in both cases, the crystalline phases of α-Al and Al3Y get formed.1 Using high pressure, we have provided a dense homogeneous alloy structure with abnormally α-Al-supersaturated solid solution and finely divided aluminides in metastable eutectics with high hardness.
Keywords: A1. Crystal structure A1. Eutectics A1. Supersaturated solutions A1. X-ray diffraction A2. Growth from melt B1. Alloys
1. Introduction The progressing science and technology require metal products of higher quality. Aluminum-based alloys used in various industries face specifically high requirements: optimal balance of durability, plasticity, corrosion- and heat-resistance. Better properties of such alloys can be achieved through appropriate production conditions (thermo-time processing [1], high-rate and directed crystallization [2], intensive plastic deformation [3], modifying and doping [4], die-casting [5], ultrasonic treatment [6], etc.). Doping aluminum with rare earth metals increases the durability of aluminum alloys several times [7]. Applying high pressures (hundreds of MPa and more) is one of the most promising ways to acquire better material properties [5,8–10]. It is known that melt crystallization under high pressures result in: finer alloy structure, possibly changed phase content and distribution and higher homogeneity due to less active liquation processes; the observed uniform distribution of non-metallic impurities causes better physical and mechanical properties of the alloy [5,8,9]. As compared to other casting methods [10], the density of test casts improves by 15–30% and the plasticity improves in 2–4 times. This paper considers the hypereutectic Al90Y10 alloy of the model binary Al-Y system. The Al-Y system alloys revealing more aluminum in the diagram region are used to produce multicomponent alloys based on aluminum of high mechanical properties [11,12]. For the alloys of this system, the effect of high pressure on the melt solidification
⁎
1
processes has never been thoroughly studied, either at low (~1 K/s) or high (103–106 K/s) cooling rates. This work continues the research we have conducted, see [13]. The research is aimed at studying how high pressure influences the Al90Y10 melt hardening at quick cooling (103 K/s). 2. Experimental procedure The Al90Y10 ingot is produced by metal alloying: aluminum − 99.999, yttrium − 99.99 (wt.%). The alloying technology supposes: heating Al up to 750 °C; adding one half of the Y; heating up to 1000 °C for 25–30 min; mixing; cooling down to 900 °C; adding the remaining Y; heating up to 1000 °C for 20–25 min; mixing; discharging to a cast-iron mold (d ~ 21 mm). Chemical analysis of the ingot has shown that the proportion of the main components corresponded with the reference content. The produced ingot has been used for an experiment under high pressure (9 GPa) held in a toroid-shaped chamber (Fig. 1) [14]. This is the maximum pressure available for this equipment. A finely chipped sample in a cylinder-shaped tube of hexagonal boron nitride has been placed immediately in compressing environment of lithographic stone; the butt ends of the sample contacted aluminum (A999) plates – discs of ~5 × 3 mm (diameter × height). The sample has been melted by passing alternate current, cooled - by breaking current (impulsively). The sample took the form of as a cylinder ~2 × 2 mm (diameter × height). The Table 1 herein indicates the experiment
Corresponding author. E-mail address: [email protected] (S.G. Menshikova). Low-temperature Al3Y phase – at the atmospheric pressure; high-temperature metastable Al3Y* phase – hardening under high pressure.
https://doi.org/10.1016/j.jcrysgro.2019.125164 Received 20 June 2019; Accepted 23 July 2019 Available online 23 July 2019 0022-0248/ © 2019 Elsevier B.V. All rights reserved.
Journal of Crystal Growth 524 (2019) 125164
S.G. Menshikova, et al.
Fig. 1. Camera “toroid”. 1 – Hard alloy, 2 – torus, 3 – central part in the form of lentils, 4 – heater and sample, 5 – steel rings, 6 – base plates [14].
values of temperature and pressure. The phase composition of the samples has been detected by X-ray structural analysis on a Bruker Advance installation in copper Kα-radiation. To specify the chemical composition, morphology and size of the alloy structural components, we used a Quanta-200 scanning electronic microscope and a Philips SEM 515 focused-beam electronic microscope with an EDAX attachment. The Vickers microhardness (Hv) of the structural components of the samples was measured using a PMT3M microhardnessmeter, load: 50 g, timing: 10 s. We measured the microhardness of the Al3Y primary crystals and (α-Al + Al3Y) eutectic in Sample 1, as well as the microhardness of α-Al primary crystals and (α-Al + Al3Y*) eutectic in Sample 2. We used the values of the microhardness averaged for 20 measurements. The measurement results are shown in the Table 1.
Fig. 2. X-ray diffractograms of the Al90Y10 alloy. □ – α-Al, ● – Al3Y, ○ – Al3Y*.
structure is homogeneous, no porosity or shrink holes have been found. Primary α-Al phase emerges as round-shaped dendrites; it evidences volume crystallization of the alloy under high all-around pressure, with no coarse primary yttrium aluminides. According to X-ray spectral microanalysis, the α-Al phase also includes 0.3% of Y (point 1 in Fig. 2b). According to the reference [17], the solubility of yttrium in aluminum at 620, 600 and 500 °C amounts to respectively: 0.046; 0.039; 0.024%. The maximum solubility of yttrium in aluminum, found through extrapolation, is 0.052% [16]. Therefore, we have produced an abnormally supersaturated solid solution Al(Y) with a microhardness of 730 MPa. The interdendritic space is occupied by finely differentiated metastable eutectics (α-Al + Al3Y*). The content of the alloy in the eutectic layer, 1 μm thickness: Al 96% and Y 3% (point 2 in Fig. 2b). The microhardness of the eutectic areas in Sample 2 is ~5 times higher than that in Sample 1.
3. Results According to X-ray structural analysis, Sample 1 reveals two phases of α-Al и Al3Y (Fig. 2). The α-Al lattice constant amounts to 0.4049 ± 0.0002 nm which coincides with the known data. Al3Y is a low-temperature phase with a hex lattice (a = 0.6189 ± 0.0001 and c = 2.11840 ± 0003 nm which also corresponds with the known reference values). The structure of Sample 1 shows large primary Al3Y crystals and double eutectics (α-Al + Al3Y) (Fig. 3a). The alloy is found to have pores (insert in Fig. 3a). The experiment under high pressure has taken the ingot area of the minimal porosity. Sample 2 proves to have two crystalline phases: α-Al and Al3Y* (Fig. 2). The lines of the Al3Y* phase, with a relevant offset towards the region of bigger angles, correspond with the lines of the metastable high-temperature Al3Y phase (L12 cubic lattice, Pm3m space group, 0.4321 nm lattice period), but have a far less lattice period (a = 0.4241 ± 0.0002 nm). The work [15] shows that under less pressures, 1.5–6.4 GPa, and at temperatures of 700–800 °C, the lowtemperature Al3Y phase with a hexagonal lattice converts to the hightemperature Al3Y phase with a BaPb3-type structure. The structure of Sample 2 is given in Fig. 3b. Fig. 3b shows that, when cooled from 1800 °C at 103 K/s under 9 GPa with the given build type in a toroidshaped chamber, the melt hardening is hypoeutectic. It is possible in case of high crystallization interface supercooling [16]. The sample
4. Conclusion The sample produced through high-pressure all-around compression shows no pores or shrink holes unlike the sample produced through casting under atmospheric pressure [18,19]. Porosity, like many other defects resulting from crystallization, emerges in two-phase zone. During phase transition, the alloy gets compressed, which leads to cavities spare from the metal (shrink holes and pores). The high pressures we apply during melt crystallization results in filling of such cavities and acts similarly with quick cooling. Since the crystallization rate under high pressure grows by several times, the structure becomes more uniform and finely divided, without shrink holes. Eventually, we have a modified structure where pressure is the main modifier during
Table 1 Conditions for obtaining of the Al90Y10 samples and the microhardness value of their structural components. Sample No.
Conditions for sample preparation
Microhardness Hv ( ± 50 MPa)
1 2
Alloying metals in corundum crucibles in the Tamman furnace with discharge to cast-iron mold at the atmospheric pressure 9 GPa, 1800 °C*, 103 K/s direct heating
Al3Y crystals 4600 eutectic 530 α-Al dendrites 730 eutectic 2500
* Approximate temperature.
2
Journal of Crystal Growth 524 (2019) 125164
S.G. Menshikova, et al.
solution and dispersion strengthening. The findings of this paper reveal the prospects of using the method of pressurized melt solidification for modifying and changing the property level of aluminum alloys. Declaration of Competing Interest The authors declared that there is no conflict of interest. Acknowledgments The research has been sponsored by the Russian Foundation for Basic Research, Research Project 18-02-00643a. The authors sincerely thank Ms S.A. Teryoshkina and Ms M.I. Mokrushina for their assistance in X-ray phase analysis. References [1] I.G. Brodova, P.S. Popel, N.M. Barbin, N.A. Vatolin, Melts as the Basis for the Formation of the Structure and Properties of Aluminum Alloys, Ekaterinburg, 2005. [2] V.Ye. Semerenko, A.A. Kasilov, T.A. Kovalenko, J. Khar. Univ. Phys. Ser. «Nucl. Particl., Fields» 53 (2012) 991. [3] N. Boucharat, R. Herert, H. Rösner, R. Valiev, G. Wilde, Scr. Mater. 53 (2005) 7. [4] V.I. Napalkov, Doping and Modifying of Aluminum and Magnesium, Moscow, 2002. [5] E.N. Sosenushkin, L.S. Frantsuzova, E.M. Kozlova, Metal. Sci. Heat Treat. 6 (2015). [6] G.A. Kosnikov, A.S. Eldarkhanov, V.V. Serbin, A.V. Kalmykov, Non-Ferr. Met. 3 (2016). [7] L.F. Mondolfo, Structure and Properties of Aluminum Alloys, Moscow, 1979. [8] L.X. Li, M. Li, W.Z. Li, Adv. Mater. Res. 320 (2011). [9] J. Sobczak, L. Drenchev, R. Asthana, Int. J. Cast. Met. Res. 25 (2012). [10] M.B. Altman, A.D. Andreev, G.A. Balakhontsev, et al., Melting and Casting of Aluminium Alloys, Moscow, 1983. [11] F. Cang, Y. Xingxing, I. Akihisa, L. Chain-Tsuan, K. Shen Xiaoping, L. Peter, Mater. Res. 22 (2019) 1. [12] I. Inoue, Prog. Mater. Sci. 43 (1998). [13] S.G. Menshikova, I.G. Shirinkina, I.G. Brodova, V.V. Brazhkin, Russ. Metall. (Metally) 2 (2019). [14] V.V. Brazhkin, Phys.-Mater. Sciences in the Form of a Scientific Report, Moscow, 1996. [15] J.F. Cannon, H.T. Hall, J. Less-Com. Met. 40 (1975) 3. [16] A.Ya. Shinyaev, A.I. Litvintsev, O.G. Pivkina, Metal. Sci. Heat Treat. 2 (1983). [17] E.M. Drits, E.S. Kadaner, D.S. Nguyen, Izv. Acad. Sci. USSR Met. 1 (1969). [18] V.A. Rybkin, Control of Materials and Work in the Foundry, Moscow, 1980. [19] Yu.F. Voronin, Improving the Quality of Casting. Systems Approach, Moscow, 2007.
Fig. 3. Microstructure of the Al90Y10 alloy: sample 1 (a), sample 2 (b). 1 – αAl, 2 – eutectic (α-Al + Al3Y*).
hardening. The joint effect of pressure, overheating, and cooling rate under the selected conditions of hardening of the Al90Y10 melt have resulted in a dense uniform structure with abnormally α-Al supersaturated solid solution, finely-divided aluminides in metastable eutectics, and strong mechanical properties of the alloy due to solid-
3
Contents lists available at ScienceDirect
Journal of Crystal Growth journal homepage: www.elsevier.com/locate/jcrysgro
Features of the Al90Y10 alloy structure during solidification under high pressure
T
S.G. Menshikovaa, , V.V. Brazhkinb, V.I. Lad'yanova, B.E. Pushkareva ⁎
a b
Udmurt Federal Research Center, Ural Branch, Russian Academy of Sciences, T. Baramzina Str., 34, 426067 Izhevsk, Russia L.F. Vereshagin Institute of High Pressure Physics, Russian Academy of Sciences, Kaluga Highway, 14, 108840 Moscow, Russia
ARTICLE INFO
ABSTRACT
Communicated by P.G. Peter Galenko
Using the methods of durametry, X-ray structural analysis, optical and electronic microscopy, we have compared the structures of the Al90Y10 hypereutectic alloy (hereinafter at.% is given) obtained at the atmospheric pressure and that produced with quick cooling under pressure of 9 GPa. It has been demonstrated that, in both cases, the crystalline phases of α-Al and Al3Y get formed.1 Using high pressure, we have provided a dense homogeneous alloy structure with abnormally α-Al-supersaturated solid solution and finely divided aluminides in metastable eutectics with high hardness.
Keywords: A1. Crystal structure A1. Eutectics A1. Supersaturated solutions A1. X-ray diffraction A2. Growth from melt B1. Alloys
1. Introduction The progressing science and technology require metal products of higher quality. Aluminum-based alloys used in various industries face specifically high requirements: optimal balance of durability, plasticity, corrosion- and heat-resistance. Better properties of such alloys can be achieved through appropriate production conditions (thermo-time processing [1], high-rate and directed crystallization [2], intensive plastic deformation [3], modifying and doping [4], die-casting [5], ultrasonic treatment [6], etc.). Doping aluminum with rare earth metals increases the durability of aluminum alloys several times [7]. Applying high pressures (hundreds of MPa and more) is one of the most promising ways to acquire better material properties [5,8–10]. It is known that melt crystallization under high pressures result in: finer alloy structure, possibly changed phase content and distribution and higher homogeneity due to less active liquation processes; the observed uniform distribution of non-metallic impurities causes better physical and mechanical properties of the alloy [5,8,9]. As compared to other casting methods [10], the density of test casts improves by 15–30% and the plasticity improves in 2–4 times. This paper considers the hypereutectic Al90Y10 alloy of the model binary Al-Y system. The Al-Y system alloys revealing more aluminum in the diagram region are used to produce multicomponent alloys based on aluminum of high mechanical properties [11,12]. For the alloys of this system, the effect of high pressure on the melt solidification
⁎
1
processes has never been thoroughly studied, either at low (~1 K/s) or high (103–106 K/s) cooling rates. This work continues the research we have conducted, see [13]. The research is aimed at studying how high pressure influences the Al90Y10 melt hardening at quick cooling (103 K/s). 2. Experimental procedure The Al90Y10 ingot is produced by metal alloying: aluminum − 99.999, yttrium − 99.99 (wt.%). The alloying technology supposes: heating Al up to 750 °C; adding one half of the Y; heating up to 1000 °C for 25–30 min; mixing; cooling down to 900 °C; adding the remaining Y; heating up to 1000 °C for 20–25 min; mixing; discharging to a cast-iron mold (d ~ 21 mm). Chemical analysis of the ingot has shown that the proportion of the main components corresponded with the reference content. The produced ingot has been used for an experiment under high pressure (9 GPa) held in a toroid-shaped chamber (Fig. 1) [14]. This is the maximum pressure available for this equipment. A finely chipped sample in a cylinder-shaped tube of hexagonal boron nitride has been placed immediately in compressing environment of lithographic stone; the butt ends of the sample contacted aluminum (A999) plates – discs of ~5 × 3 mm (diameter × height). The sample has been melted by passing alternate current, cooled - by breaking current (impulsively). The sample took the form of as a cylinder ~2 × 2 mm (diameter × height). The Table 1 herein indicates the experiment
Corresponding author. E-mail address: [email protected] (S.G. Menshikova). Low-temperature Al3Y phase – at the atmospheric pressure; high-temperature metastable Al3Y* phase – hardening under high pressure.
https://doi.org/10.1016/j.jcrysgro.2019.125164 Received 20 June 2019; Accepted 23 July 2019 Available online 23 July 2019 0022-0248/ © 2019 Elsevier B.V. All rights reserved.
Journal of Crystal Growth 524 (2019) 125164
S.G. Menshikova, et al.
Fig. 1. Camera “toroid”. 1 – Hard alloy, 2 – torus, 3 – central part in the form of lentils, 4 – heater and sample, 5 – steel rings, 6 – base plates [14].
values of temperature and pressure. The phase composition of the samples has been detected by X-ray structural analysis on a Bruker Advance installation in copper Kα-radiation. To specify the chemical composition, morphology and size of the alloy structural components, we used a Quanta-200 scanning electronic microscope and a Philips SEM 515 focused-beam electronic microscope with an EDAX attachment. The Vickers microhardness (Hv) of the structural components of the samples was measured using a PMT3M microhardnessmeter, load: 50 g, timing: 10 s. We measured the microhardness of the Al3Y primary crystals and (α-Al + Al3Y) eutectic in Sample 1, as well as the microhardness of α-Al primary crystals and (α-Al + Al3Y*) eutectic in Sample 2. We used the values of the microhardness averaged for 20 measurements. The measurement results are shown in the Table 1.
Fig. 2. X-ray diffractograms of the Al90Y10 alloy. □ – α-Al, ● – Al3Y, ○ – Al3Y*.
structure is homogeneous, no porosity or shrink holes have been found. Primary α-Al phase emerges as round-shaped dendrites; it evidences volume crystallization of the alloy under high all-around pressure, with no coarse primary yttrium aluminides. According to X-ray spectral microanalysis, the α-Al phase also includes 0.3% of Y (point 1 in Fig. 2b). According to the reference [17], the solubility of yttrium in aluminum at 620, 600 and 500 °C amounts to respectively: 0.046; 0.039; 0.024%. The maximum solubility of yttrium in aluminum, found through extrapolation, is 0.052% [16]. Therefore, we have produced an abnormally supersaturated solid solution Al(Y) with a microhardness of 730 MPa. The interdendritic space is occupied by finely differentiated metastable eutectics (α-Al + Al3Y*). The content of the alloy in the eutectic layer, 1 μm thickness: Al 96% and Y 3% (point 2 in Fig. 2b). The microhardness of the eutectic areas in Sample 2 is ~5 times higher than that in Sample 1.
3. Results According to X-ray structural analysis, Sample 1 reveals two phases of α-Al и Al3Y (Fig. 2). The α-Al lattice constant amounts to 0.4049 ± 0.0002 nm which coincides with the known data. Al3Y is a low-temperature phase with a hex lattice (a = 0.6189 ± 0.0001 and c = 2.11840 ± 0003 nm which also corresponds with the known reference values). The structure of Sample 1 shows large primary Al3Y crystals and double eutectics (α-Al + Al3Y) (Fig. 3a). The alloy is found to have pores (insert in Fig. 3a). The experiment under high pressure has taken the ingot area of the minimal porosity. Sample 2 proves to have two crystalline phases: α-Al and Al3Y* (Fig. 2). The lines of the Al3Y* phase, with a relevant offset towards the region of bigger angles, correspond with the lines of the metastable high-temperature Al3Y phase (L12 cubic lattice, Pm3m space group, 0.4321 nm lattice period), but have a far less lattice period (a = 0.4241 ± 0.0002 nm). The work [15] shows that under less pressures, 1.5–6.4 GPa, and at temperatures of 700–800 °C, the lowtemperature Al3Y phase with a hexagonal lattice converts to the hightemperature Al3Y phase with a BaPb3-type structure. The structure of Sample 2 is given in Fig. 3b. Fig. 3b shows that, when cooled from 1800 °C at 103 K/s under 9 GPa with the given build type in a toroidshaped chamber, the melt hardening is hypoeutectic. It is possible in case of high crystallization interface supercooling [16]. The sample
4. Conclusion The sample produced through high-pressure all-around compression shows no pores or shrink holes unlike the sample produced through casting under atmospheric pressure [18,19]. Porosity, like many other defects resulting from crystallization, emerges in two-phase zone. During phase transition, the alloy gets compressed, which leads to cavities spare from the metal (shrink holes and pores). The high pressures we apply during melt crystallization results in filling of such cavities and acts similarly with quick cooling. Since the crystallization rate under high pressure grows by several times, the structure becomes more uniform and finely divided, without shrink holes. Eventually, we have a modified structure where pressure is the main modifier during
Table 1 Conditions for obtaining of the Al90Y10 samples and the microhardness value of their structural components. Sample No.
Conditions for sample preparation
Microhardness Hv ( ± 50 MPa)
1 2
Alloying metals in corundum crucibles in the Tamman furnace with discharge to cast-iron mold at the atmospheric pressure 9 GPa, 1800 °C*, 103 K/s direct heating
Al3Y crystals 4600 eutectic 530 α-Al dendrites 730 eutectic 2500
* Approximate temperature.
2
Journal of Crystal Growth 524 (2019) 125164
S.G. Menshikova, et al.
solution and dispersion strengthening. The findings of this paper reveal the prospects of using the method of pressurized melt solidification for modifying and changing the property level of aluminum alloys. Declaration of Competing Interest The authors declared that there is no conflict of interest. Acknowledgments The research has been sponsored by the Russian Foundation for Basic Research, Research Project 18-02-00643a. The authors sincerely thank Ms S.A. Teryoshkina and Ms M.I. Mokrushina for their assistance in X-ray phase analysis. References [1] I.G. Brodova, P.S. Popel, N.M. Barbin, N.A. Vatolin, Melts as the Basis for the Formation of the Structure and Properties of Aluminum Alloys, Ekaterinburg, 2005. [2] V.Ye. Semerenko, A.A. Kasilov, T.A. Kovalenko, J. Khar. Univ. Phys. Ser. «Nucl. Particl., Fields» 53 (2012) 991. [3] N. Boucharat, R. Herert, H. Rösner, R. Valiev, G. Wilde, Scr. Mater. 53 (2005) 7. [4] V.I. Napalkov, Doping and Modifying of Aluminum and Magnesium, Moscow, 2002. [5] E.N. Sosenushkin, L.S. Frantsuzova, E.M. Kozlova, Metal. Sci. Heat Treat. 6 (2015). [6] G.A. Kosnikov, A.S. Eldarkhanov, V.V. Serbin, A.V. Kalmykov, Non-Ferr. Met. 3 (2016). [7] L.F. Mondolfo, Structure and Properties of Aluminum Alloys, Moscow, 1979. [8] L.X. Li, M. Li, W.Z. Li, Adv. Mater. Res. 320 (2011). [9] J. Sobczak, L. Drenchev, R. Asthana, Int. J. Cast. Met. Res. 25 (2012). [10] M.B. Altman, A.D. Andreev, G.A. Balakhontsev, et al., Melting and Casting of Aluminium Alloys, Moscow, 1983. [11] F. Cang, Y. Xingxing, I. Akihisa, L. Chain-Tsuan, K. Shen Xiaoping, L. Peter, Mater. Res. 22 (2019) 1. [12] I. Inoue, Prog. Mater. Sci. 43 (1998). [13] S.G. Menshikova, I.G. Shirinkina, I.G. Brodova, V.V. Brazhkin, Russ. Metall. (Metally) 2 (2019). [14] V.V. Brazhkin, Phys.-Mater. Sciences in the Form of a Scientific Report, Moscow, 1996. [15] J.F. Cannon, H.T. Hall, J. Less-Com. Met. 40 (1975) 3. [16] A.Ya. Shinyaev, A.I. Litvintsev, O.G. Pivkina, Metal. Sci. Heat Treat. 2 (1983). [17] E.M. Drits, E.S. Kadaner, D.S. Nguyen, Izv. Acad. Sci. USSR Met. 1 (1969). [18] V.A. Rybkin, Control of Materials and Work in the Foundry, Moscow, 1980. [19] Yu.F. Voronin, Improving the Quality of Casting. Systems Approach, Moscow, 2007.
Fig. 3. Microstructure of the Al90Y10 alloy: sample 1 (a), sample 2 (b). 1 – αAl, 2 – eutectic (α-Al + Al3Y*).
hardening. The joint effect of pressure, overheating, and cooling rate under the selected conditions of hardening of the Al90Y10 melt have resulted in a dense uniform structure with abnormally α-Al supersaturated solid solution, finely-divided aluminides in metastable eutectics, and strong mechanical properties of the alloy due to solid-
3