Amorphous Hollow Sphere Foams for Customizable Porosity
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Solution Overview
Problem
Current methods for producing foams from metallic glasses are limited in achieving high porosity and customizable cell size, wall thickness, internal cell pressure, and material strength, making it difficult to meet the varied requirements of different applications.
Innovation Solution
The method involves forming amorphous hollow spheres with internal pressures and heating them above their glass transition temperature to apply a pressure differential, allowing them to expand or contract and bond, creating cellular solids with customizable properties by controlling the pressure and surface treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to produce foams from metallic glasses, then the foam production process is simple, but the porosity and cell size customization are limited
Solution Approach 1:
The patent applies preliminary action by pre-forming hollow spheres with controlled wall thickness and internal structure before the foaming process. These pre-formed spheres serve as templates that dictate the final cell structure, enabling precise control over cell size and shape while simplifying the subsequent foaming process.
Solution Approach 2:
The patent utilizes parameter changes by controlling the glass transition temperature through alloy composition and applying controlled heating rates during the foaming process. By adjusting these parameters, the patent achieves precise control over cell size, porosity, and wall thickness without complicating the overall manufacturing process.
2Adaptability or versatility
If hollow spheres are made by coating sacrificial spheres with crystalline metals, then the hollow sphere structure is achieved, but the method is difficult to engineer and limited in material selection
Solution Approach 1:
The patent employs disposable sacrificial cores that are easily deposited and removed. These temporary cores are coated with amorphous metal layers and then dissolved or evaporated, leaving hollow spheres that can be used as templates for various amorphous metal foams. This approach enables versatile material selection while maintaining ease of manufacture.
Solution Approach 2:
The patent creates a universal method that works with multiple amorphous metal alloys and compositions. The same basic process of coating sacrificial spheres with amorphous metal and removing the core can be applied to different material systems, enabling versatile foam production across various material types without requiring system-specific procedures.
3Strength
If high strength amorphous materials are used, then the foam strength and stiffness are improved, but the control over foam density and cell structure becomes more difficult
Solution Approach 1:
The patent applies segmentation by using multiple hollow spheres of different sizes and wall thicknesses in the foam structure. This allows independent control of local properties, enabling the overall foam to achieve high strength through optimized local cell structures while maintaining precise control over bulk density and cell size distribution.
Solution Approach 2:
The patent implements local quality by varying the wall thickness and internal structure of individual hollow spheres within the foam. This enables different regions of the foam to have optimized properties for strength while maintaining controlled density and cell structure throughout the material.
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
This approach enables the production of foams with a range of densities, strengths, and stiffnesses, exceeding the properties of conventional materials, and allows for the creation of both open and closed cell structures with high specific strengths and moduli.
Implementation Method 1
heating them above their glass transition temperature
Implementation Method 2
applying a pressure differential between the internal pressure of the at least one hollow sphere and the pressure of the atmosphere within the confining body
Data Source
AI summary
Novel cellular solids and foams from amorphous materials with a glass transition temperature (Tg) and methods of forming such materials are provided. In particular, foams are formed by expanding or compressing hollow spheres made of a high strength amorphous material, which is defined as a material having high strength characteristics, but also possessing a glass transition within a confined space. Using such a method, it has been unexpectedly found that it is possible to make cellular structures, including both open and closed cell foams, with customizable properties from materials that have been inaccessible with conventional methods. Moreover, based on calculations high specific strengths and stiffnesses are expected.