[Paper Review] Development of next-generation light-weight ternary Mg--Al--Li alloys for beampipe applications in particle accelerators

Kamaljeet Singh, Kangkan Goswami+2 more|arXiv (Cornell University)|Jan 19, 2026

Magnesium Alloys: Properties and Applications0 citations

TL;DR

The paper designs Mg–Al–Li ternary alloys to improve the figure of merit X0 E^(1/3) for accelerator beampipes by achieving higher radiation length while maintaining mechanical stiffness, using Thermo-Calc phase modeling and DFT-based elastic properties.

ABSTRACT

The current study reports the design of advanced light-weight materials for high-energy accelerator beampipe applications. The objective is to optimize the combined requirements of high radiation length and stiffness properties of the designed materials. The present study targets conventional beampipe materials such as aluminum, titanium, and stainless steel as primary performance benchmarks. These conventional beampipes are used at synchrotron radiation sources, such as Indus-1 and Indus-2 in India, the Nuclotron-based Ion Collider Facility in Russia, and the ring synchrotron facility SIS 100/300 at the Facility for Antiproton and Ion Research in Germany. In this context, a series of ternary Mg--Al--Li alloys is systematically investigated to enhance the figure of merit. Two aluminum--rich alloys, A1 ($\mathrm{Al_{61.5}Li_{10.8}Mg_{27.7}}$) and A2 ($\mathrm{Al_{66}Li_{19.4}Mg_{14.6}}$), along with three magnesium-rich alloys, M1 ($\mathrm{Al_{23.9}Li_{29.3}Mg_{46.8}}$), M2 ($\mathrm{Al_{19}Li_{20.6}Mg_{60.4}}$), and M3 ($\mathrm{Al_{39.8}Li_{20.1}Mg_{40.1}}$) are explored. Thermodynamic stability, density, liquidus temperature, and phases are evaluated using Latin hypercube sampling within the Thermo-Calc TC-Python framework. Elastic properties are obtained from density functional theory calculations performed using the Vienna extit{Ab Initio} Simulation Package. Our results show that, although the elastic moduli ($E$) of the investigated Mg-Al-Li alloys are comparable to those of conventional beampipe materials, their significantly higher radiation lengths ($X_0$) lead to an overall improvement in the figure of merit $X_0 E^{1/3}$.

Motivation & Objective

• Motivate the need for higher X0E^(1/3) beampipe materials with reduced material interaction in high-energy accelerators.
• Propose Mg–Al–Li ternary alloys as candidates to improve radiation length while preserving mechanical integrity.
• Assess thermodynamic stability, density, radiation length, and elastic properties of selected alloys.
• Quantify the figure of merit X0E^(1/3) and compare with conventional materials.
• Highlight implications for future high-precision vertex reconstruction in detectors such as ALICE 3.

Proposed method

• Use Latin hypercube sampling within Thermo-Calc TC-Python to evaluate thermodynamic stability, phase fields, density, and radiation length of Mg–Al–Li alloys.
• Compute element-wise radiation lengths with a weighted inverse sum approach for multi-component systems.
• Obtain elastic properties from first-principles DFT calculations using VASP with PBE-GGA and PAW pseudopotentials.
• Apply Voigt–Reuss–Hill averaging to derive bulk and shear moduli and the isotropic elastic modulus E.
• Analyse solidification paths and phase evolution with Gulliver–Scheil non-equilibrium solidification modeling.
• Present a comparative table of X0, E, density, and X0E^(1/3) against benchmark materials.

Experimental results

Research questions

• RQ1 Can Mg–Al–Li ternary alloys achieve higher radiation length X0 while maintaining sufficient elastic modulus E for beampipe applications?
• RQ2 How do aluminum-rich versus magnesium-rich compositions compare in terms of X0, E, density, and the combined figure of merit X0E^(1/3)?
• RQ3 What thermodynamic phase equilibria and solidification pathways are expected for the proposed compositions?
• RQ4 Do the designed alloys surpass conventional beampipe materials (Al, stainless steel, Al–Ti–V) in the metric X0E^(1/3)?

Key findings

• All designed Mg–Al–Li alloys show significantly higher radiation lengths than conventional beampipe materials.
• Al-rich alloys reach X0 values around 0.118–0.124 m with E in the ~100–120 GPa range.
• Mg-rich alloys achieve X0 up to 0.1703 m but with lower E (~27–66 GPa for different compositions).
• The best balance is found for alloy M3, with X0 = 0.1428 m, E = 104.6 GPa, yielding the highest reported X0E^(1/3) = 0.6729 among the studied compositions.
• Table-computed X0E^(1/3) values show Mg–Al–Li alloys outperform stainless steel (≈0.102) and Al (≈0.37), and exceed Al–Ti–V (≈0.416).
• Overall, Mg–Al–Li alloys offer a favorable trade-off between radiation transparency and mechanical performance, particularly near the interaction region in accelerators.