La-Fe-Si Magnetocaloric Alloy Composition for Reduced Brittleness
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Solution Overview
Problem
Current magnetocaloric materials face challenges such as brittleness, toxicity, high cost, low Curie temperature, and inadequate magnetocaloric effects at desired magnetic fields, limiting their application in efficient refrigeration and heat pumping systems.
Innovation Solution
Modification of the La—Fe—Si alloy system by incorporating small amounts of Al, Ga, and In to enhance mechanical stability and maintain or improve magnetocaloric effects, along with substitution of Fe with Co, Mn, Cr, and V, and inclusion of interstitial hydrogen, to create alloys with improved handleability and tunable magnetocaloric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If La(Fe,Si)13 magnetocaloric materials are used, then large magnetocaloric effect is achieved, but excessive brittleness causes decrepitation and disintegration during handling and thermal-magnetic cycling
Solution Approach 1:
The patent applies parameter changes by systematically varying the alloy composition parameters (substituting Fe with Co, Mn, Cr, or V at controlled concentrations of 0.05≤w≤0.1, and adjusting Si content where 1.1≤z≤1.9) to optimize the balance between mechanical stability and magnetocaloric performance. This compositional parameter optimization reduces brittleness while preserving the large magnetocaloric effect, enabling the material to withstand handling and thermal-magnetic cycling without decrepitation.
Solution Approach 2:
The patent creates composite alloy systems by combining La-Fe-Si base material with substituting elements (Co, Mn, Cr, V) and interstitial hydrogen. This composite approach integrates multiple elements with complementary properties: the base La(Fe,Si)13 provides large magnetocaloric effect, while the substituting elements enhance mechanical stability and reduce brittleness, creating a composite material that simultaneously achieves both required properties.
2Temperature
If magnetocaloric materials with Curie temperature near 350K are developed, then room temperature application is enabled, but magnetocaloric effect at 2 Tesla or lower magnetic field is insufficient
Solution Approach 1:
The patent utilizes parameter changes by precisely controlling the alloy composition to achieve Curie temperature near 350K while maintaining large magnetocaloric effect at low magnetic fields (≤2T). The substitution of Fe with specific elements and adjustment of Si content allows tuning of both Curie temperature and magnetocaloric effect magnitude simultaneously, overcoming the trade-off between operating temperature and effect strength.
3Ease of operation
If La—Fe—Si alloy system is modified with additional elements, then mechanical stability and handleability are improved, but alloy composition complexity increases
Solution Approach 1:
The patent applies local quality by introducing elements at specific local positions in the crystal structure: substituting elements (Co, Mn, Cr, V) replace Fe at specific lattice sites, and interstitial hydrogen occupies interstitial positions. This localized modification approach improves mechanical stability and handleability through targeted compositional changes rather than uniform mixing, minimizing overall composition complexity while achieving the desired mechanical properties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The modified alloys exhibit reduced brittleness, improved mechanical stability, and preserved or enhanced magnetocaloric effects, enabling their use in magnetocaloric heat pumping devices without decrepitation, with tunable magnetocaloric effects between 170 K and 350 K and increased thermal conductivity.
Implementation Method 1
The ability of magnetic materials to change their temperature due to variation of applied magnetic field (magnetocaloric effect, MCE)
Implementation Method 2
including interstitial hydrogen in the modified La—Fe—Si based alloy composition
Data Source
AI summary
A magnetocaloric material comprising a La—Fe—Si based alloy composition that is compositionally modified to include a small but effective amount of at least one of Al, Ga, and In to improve mechanical stability of the alloy (substantially reduce alloy brittleness), improve thermal conductivity, and preserve comparable or provide improved magnetocaloric effects. The alloy composition may be further modified by inclusion of at least one of Co, Mn, Cr, and V as well as interstitial hydrogen.