Bulk Metallic Glass Feature Integration via Thermoplastic Forming
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Solution Overview
Problem
Current metal processing techniques cannot integrate functional features like keys, buttons, and sensors into metal articles due to limitations in producing thin sections with structural integrity and elasticity, leading to weak spots from material welding and inefficiencies in existing bulk metallic glass applications.
Innovation Solution
The integration of functional features into bulk metallic glass articles through controlled thermoplastic forming methods, such as blow molding, stretch molding, and compression molding, allowing for localized thin sections with varying stiffness and controlled thickness, enabling the creation of strong, durable, and elastic features within the same material as the article.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal processing techniques are used to integrate functional features into metal articles, then material welding is required to join features to the article, but this creates weak spots, leakage, breakage upon repeated use, and minimal elasticity
Solution Approach 1:
The patent merges the functional features and the article skin into a single integrated component made from the same bulk metallic glass material. The forming process simultaneously creates both the article body and the functional features (keys, buttons, switches, sensors) as monolithic integrated structures, eliminating the need for separate material joining operations and the associated weak spots and leakage issues.
Solution Approach 2:
The patent utilizes parameter changes by heating the bulk metallic glass to its supercooled liquid region (between glass transition temperature Tg and crystallization temperature Tx) where the material becomes formable. This temporary parameter change allows the material to be molded into complex shapes with integrated thin-section features, then cooled to restore its solid structural properties.
2Ease of operation
If metal processing techniques are used to produce thin sections for functional features, then the required stroke functionality (large deformation at low applied force) can be achieved, but the structural integrity of thicker sections is compromised
Solution Approach 1:
The patent applies local quality by creating spatially varying thickness within the bulk metallic glass article. Thin sections (e.g., 0.5mm to 2mm) are formed in specific locations where functional features require large deformation and stroke, while thicker sections maintain structural integrity. The material properties and geometry are locally optimized to provide different functional characteristics in different regions of the same component.
3Ease of operation
If conventional metals are used for functional features, then material availability is good, but elasticity is limited which prohibits integration of features requiring large deformation
Solution Approach 1:
The patent exploits parameter changes by utilizing the bulk metallic glass's supercooled liquid region where the material transitions from a rigid solid to a formable viscous state. During forming operations, the material is heated to temperatures between Tg and Tx where it exhibits high formability and can be molded into complex shapes with thin sections, then cooled to restore its solid elastic properties for functional operation.
4Manufacturing precision
If bulk metallic glass is used to integrate functional features through thermoplastic forming, then localized thin sections with varying stiffness can be created, but the processing time must be controlled within the crystallization time window
Solution Approach 1:
The patent employs feedback control by monitoring and controlling the forming process parameters (temperature, pressure, time) to ensure the bulk metallic glass remains within its supercooled liquid region during forming. The process is designed to complete within the crystallization time window, with feedback mechanisms ensuring the material does not crystallize during forming, thereby maintaining amorphous structure and desired 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
This approach allows for the precise and repeatable fabrication of thin sections within bulk metallic glass articles, enhancing their formability and durability, enabling the integration of functional features like keys, sensors, and bellows with improved performance and reliability compared to traditional welding methods.
Implementation Method 1
A unique property of BMG is that they have a supercooled liquid region (SCLR), ΔTsc, which is a relative measure of the stability of the viscous liquid regime. The SCLR is defined by the temperature difference between the onset of crystallization, Tx, and the glass transition temperature, Tg of the particular BMG alloy.
Implementation Method 2
Superplastic forming (SPF) of an amorphous metal alloy involves heating it into the SCLR and forming it under an applied pressure. The method is similar to the processing of thermoplastics, where the formability, which is inversely proportional to the viscosity, increases with increasing temperature.
Implementation Method 3
Crystallization of the amorphous metal alloy must be avoided for several reasons. First, it degrades the mechanical properties of the amorphous metal alloy. From a processing standpoint, crystallization limits the processing time for hot-forming operation because the flow in crystalline materials is order of magnitude higher than in the liquid amorphous metal alloy.
Data Source
AI summary
An article comprising a bulk metallic glass skin having one or more functional features integrated therein is described and a method of forming the same is described. The one or more functional features exhibit a variation in stiffness between the one or more functional features and the bulk metallic glass skin that is defined by an applied force over an achieved deformation. The stiffness of each of the one or more functional features is at least 1000 times less than an average stiffness of the bulk metallic glass skin.