Synthesis, microstructural evolution, and compaction behavior of Mg30-Al25-Ti25-Li15-Si5 lightweight high-entropy alloys synthesized via mechanical alloying

Hany R. Ammar; Subbarayan Sivasankaran; Fahad A. Al-Mufadi

doi:10.2478/msp-2025-0014

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Synthesis, microstructural evolution, and compaction behavior of Mg30-Al25-Ti25-Li15-Si5 lightweight high-entropy alloys synthesized via mechanical alloying

Materials Science-Poland

Volume 43 (2025): Issue 1 (March 2025)

By: Hany R. Ammar, Subbarayan Sivasankaran and Fahad A. Al-Mufadi

Open Access

|Mar 2025

Figures & Tables

Table 1

A list of low-density elements selected for the present study [14].

Element	Atomic number	Atomic radius (nm)	Melting temperature (K)	Density (g/cm³)
Mg	24	0.1249	923	1.74
Al	26	0.1241	933.3	2.70
Ti	13	0.1432	1,941	4.50
Li	27	0.1251	453.5	0.53
Si	14	0.1153	1,687	2.33

Table 2

Chemical composition of the developed Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ LWHEA.

Mg	Al		Ti		Li		Si
Wt%	At%	Wt%	At%	Wt%	At%	Wt%	At%	Wt%	At%
30	24.57	25	18.45	25	10.40	15	43.03	5	3.55

Table 3

Ball milling processing parameters of the developed Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ LWHEA.

Alloy code	Chemical composition	PBR	Milling speed	Milling time (h)
L1-0	Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅	15:1	300 rpm	0 (premixed Conditions)
L1-5				5
L1-10				10
L1-20				20

Table 4

Properties of the elements used in the present study to develop the Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ alloy.

Element	Atomic number	Atomic radius (nm)	Pauling electronegativity	VEC	Atomic weight	Melting temperature (K)	Density (g/cm³)
Mg	24	0.1249	1.660	6	51.9961	2,180	7.2
Al	26	0.1241	1.833	8	55.8450	1,811	7.9
Ti	13	0.1432	1.610	3	26.9815	933	2.7
Li	27	0.1251	1.880	9	58.9332	1,768	8.9
Si	14	0.1153	1.900	4	28.0855	1,687	2.3

Table 5

Enthalpy of mixing ( $H_{mix}^{AB}$ ) between each pair of elements in the Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ developed alloy.

Element	Mg	Al	Ti	Li	Si
Mg	Mg	−2	16	0	−26
Al	−2	Al	−30	−4	−19
Ti	16	−30	Ti	34	−66
Li	0	−4	34	Li	−30
Si	−26	−19	−66	−30	Si

Bold value represents the element symbols.

Table 6

Physicochemical and thermodynamic properties for the Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ developed alloy powders via MA.

Alloy code	Mixing enthalpy, ΔH _mix (kJ/mol)	Entropy of mixing, ΔS _mix (J/mol K)	Gibbs free energy, $Δ G_{mix}$ (J/mol)	Melting temperature, T _m (K)	Thermodynamic parameter, Ω	Mean atomic radius, $\bar{r}$ (nm)	Atomic size difference, δ (%)	Valency electron concentration, VEC	Difference in Pauling electronegativity, $Δ X$	Density, ρ (g/cm³)
L1-0, L1-5, L1-10, and L1-20	−0.4205	11.42	−3,823	855.8	15.82	0.1504	5.93%	−0.4205	11.42	1.704

Surface morphology of as-received elemental powders used to synthesize LWHEA in this work by SEM: (a) Mg, (b) Al, (c) Ti, and (d) Si.

SEM images of the microstructures of MAed Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ LWHEAs milled for different times (5, 15, and 20 h) showing powder surface morphology: (a) L1-5 h, (b) L1-10 h, and (c) L1-20 h.

SEM images of the microstructures with EDAX analyses of MAed Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ LWHEAs milled for different times (5, 15, and 20 h) showing element composition (both wt% and at%): (a) L1-5 h, (b) L1-10 h, and (c) L1-20 h.

SEM images of the microstructures with elemental mapping of MAed Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ LWHEAs milled for different times (5, 15, and 20 h) showing the distribution of the incorporated elements and alloy formation (first from left image: SE SEM microstructure; immediate right of four images: mapping of Mg, Al, Ti, and Si): (a) L1-5 h, (b) L1-10 h, and (c) L1-20 h.

XRD peaks of the as-received elemental powders of (a) Mg, (b) Al, (c) Ti, (d) Li, and (e) Si.

XRD patterns of the milled Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ LWHEA powders for different durations: (a) L1-0 h, (b) L1-5 h, (c) L1-10 h, and (d) L1-20 h samples.

Scherrer model: (a) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (0 h), (b) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (5 h), (c) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (10 h), and (d) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (20 h).

Table 7

Estimation of the size and strain for different milled time durations of Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ LWHEA powders.

Sample/model	Parameter	Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (0 h)	Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (5 h)	Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (10 h)	Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (20 h)
Scherrer	Size (D) (nm)	1422.14	1066.7100	719.3300	618.4100
W-H UDM	Size (D) (nm)	90.5700	89.0300	81.3200	73.7200
W-H UDM	Strain (ε) (%)	0.0002	0.0013	0.0044	0.0097
W-H USDM	Size (D) (nm)	47.0200	44.5000	34.5800	30.8000
W-H USDM	Strain (ε) (%)	0.0004	0.0011	0.0032	0.0043
SSP	Size (D) (nm)	98.0400	60.2200	54.1900	42.5300
SSP	Strain (ε) (%)	0.0001	0.0008	0.0010	0.0030

W-H UDM: (a) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (0 h), (b) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (5 h), (c) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (10 h), and (d) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (20 h).

W-H USDM: (a) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (0 h), (b) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (5 h), (c) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (10 h), and (d) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (20 h).

SSP model: (a) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (0 h), (b) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (5 h), (c) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (10 h), and (d) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (20 h).

Structural properties of Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (0, 5, 10, and 20 h) nanocomposite powders milled at different durations: (a) dislocation density, (b) excess free volume, (c) SFP, and (d) N–R parameter.

HRTEM analysis of MAed LWHEA powders for different milled duration times: (a₁–a₄) BFI, (b₁–b₄) DFI, and (c₁–c₄) SAED.

HRTEM – elemental mapping and EDS analyses of the Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ (20 h) LWHEA powder samples.

HRTEM – lattice fringes of the Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ LWHEA powder samples: (a) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ 0 h, (b) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ – 5 h, (c) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ 10 h, and (d) Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ – 20 h lattice fringes correspond to (2 0 0).

Compaction behavior of Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ LWHEAs milled for different times (0, 5, 15, and 20 h) showing the behavior at various stages: (a) cold compaction at RT; (b) hot compaction at 275°C; and (c) hot compaction at 550°C.

Table 8

Variation in relative density in different stages during compaction (both cold and hot compaction) as a function of compaction pressure and temperature for Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ LWHEAs milled for different times (0, 5, 15, and 20 h).

Sample	T (°C)	P (MPa)	Compaction stages	RD (%)	Sample	T (°C)	P (MPa)	Compaction stages	RD (%)
L1-0 h	RT	20	Particle rearrangement stage	56.81	L1-5 h	RT	20	Particle rearrangement stage	55.85
		30		61.55			30		60.43
		40		65.56			40		64.30
		50		68.97			50		67.57
		60	Elastic deformation stage	71.95			60	Elastic deformation stage	70.42
		70		74.71			70		73.07
		80		77.15			80		75.40
		90		79.55			90		77.69
		100		81.70			100		79.74
		125	Plastic deformation stage	86.38			125	Plastic deformation stage	84.19
		150		90.38			150		87.98
		175		94.22			175		91.62
		200		97.40			200		94.63
	275	20	Particle rearrangement stage	61.26		275	20	Particle rearrangement stage	60.43
		30		65.34			30		64.39
		40		68.67			40		67.62
		50		71.68			50		70.54
		60	Elastic deformation stage	74.34			60	Elastic deformation stage	73.11
		70		76.80			70		75.49
		80		78.83			80		77.45
		90		80.85			90		79.40
		100		82.66			100		81.15
		125	Plastic deformation stage	87.05			125	Plastic deformation stage	85.38
		150		91.17			150		89.33
		175		94.90			175		92.91
		200		98.36			200		96.22
	550	20	Particle rearrangement stage	69.04		550	20	Particle rearrangement stage	68.47
		30		72.42			30		71.80
		40		75.13			40		74.46
		50		77.51			50		76.79
		60	Elastic deformation stage	79.73			60	Elastic deformation stage	78.98
		70		81.79			70		81.00
		80		83.56			80		82.72
		90		85.26			90		84.51
		100		86.93			100		86.03
		125	Plastic deformation stage	90.48			125	Plastic deformation stage	89.64
		150		93.82			150		92.77
		175		96.82			175		95.71
		200		99.67			200		98.48
L1-10 h	RT	20	Particle Rearrangement stage	54.22	L1-20 h	RT	20	Particle Rearrangement stage	52.33
		30		58.62			30		56.33
		40		62.25			40		59.67
		50		65.31			50		62.48
		60	Elastic deformation stage	67.97			60	Elastic deformation stage	64.92
		70		70.43			70		67.16
		80		72.59			80		69.12
		90		74.72			90		71.04
		100		76.61			100		72.75
		125	Plastic deformation stage	80.71			125	Plastic deformation stage	76.44
		150		84.19			150		79.55
		175		87.52			175		82.51
		200		90.25			200		84.94
	275	20	Particle rearrangement stage	59.40	L1-20 h	275	20	Particle rearrangement stage	57.80
		30		63.22			30		61.41
		40		66.34			40		64.35
		50		69.14			50		66.98
		60	Elastic deformation stage	71.61			60	Elastic deformation stage	69.29
		70		73.89			70		71.43
		80		75.77			80		73.18
		90		77.64			90		74.92
		100		79.30			100		76.47
		125	Plastic deformation stage	83.34			125	Plastic deformation stage	80.22
		150		87.11			150		83.70
		175		90.50			175		86.83
		200		93.64			200		89.72
	550	20	Particle rearrangement stage	69.97	L1-20 h	550	20	Particle rearrangement stage	68.88
		30		72.89			30		71.71
		40		75.29			40		74.03
		50		77.39			50		76.06
		60	Elastic deformation stage	79.33			60	Elastic deformation stage	77.94
		70		80.97			70		79.52
		80		82.58			80		81.07
		90		84.06			90		82.50
		100		85.47			100		83.85
		125	Plastic deformation stage	88.66			125	Plastic deformation stage	86.92
		150		91.46			150		89.61
		175		94.06			175		92.10
		200		96.48			200		94.42

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Articles in this issue

DOI: https://doi.org/10.2478/msp-2025-0014 | Journal eISSN: 2083-134X (formerly 2083-124X) | Journal ISSN: 2083-1331

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Language: English

Page range: 149 - 172

Submitted on: Jan 28, 2025

Accepted on: May 26, 2025

Published on: Mar 31, 2025

Published by: Wroclaw University of Science and Technology

In partnership with: Paradigm Publishing Services

Keywords:

Mg₃₀-Al₂₅-Ti₂₅-Li₁₅-Si₅ light-weight high-entropy alloys,

Mechanical alloying,

X-ray peak broadening,

Transmission electron microscope,

Hot compaction

Related subjects:

Materials sciences,

Materials sciences, other,

Nanomaterials,

Functional and smart materials,

Materials characterization and properties

© 2025 Hany R. Ammar, Subbarayan Sivasankaran, Fahad A. Al-Mufadi, published by Wroclaw University of Science and Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 43 (2025): Issue 1 (March 2025)

Synthesis, microstructural evolution, and compaction behavior of Mg30-Al25-Ti25-Li15-Si5 lightweight high-entropy alloys synthesized via mechanical alloying

Figures & Tables

Table 1

Table 2

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Table 4

Table 5

Table 6

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Figure 14

Figure 15

Table 8

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