Bulk Metallic Glass Sheet Spinning Cooling Control

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Solution Overview

Problem

The production of large-area sheets of bulk metallic glass (BMG) alloys faces challenges due to partial crystallization during slow cooling and impurities, which limits their mechanical properties and increases production costs, especially for high aspect ratio products and three-dimensional hollow products.

Innovation Solution

A device with a vacuum chamber and a spinning stage that maintains BMG in a molten state, using a heated region for melting and an unheated region for cooling, with conduits for a cooling fluid to control the cooling rate and prevent crystallization, allowing the BMG sheet to remain amorphous after solidification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If high cooling rates are used to achieve amorphous structure, then the amorphous state is maintained, but the critical thickness is limited

Engineering Contradiction:

Improveamorphous stateVSAvoidcritical thickness

Core Design Contradiction:

Stability of the object's compositionVSLength of stationary object

Solution Approach 1:

The cooling process is segmented into two distinct stages: rapid cooling in a first region to achieve amorphous structure, followed by controlled cooling in a second region to maintain thickness. This segmentation allows the material to achieve both high cooling rates for amorphous formation and sufficient thickness for structural applications.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cooling rate is dynamically adjusted across different spatial regions. The first region provides high cooling rates ( >10^5 °C/sec) to form amorphous structure, while the second region provides controlled cooling rates (<10^3 °C/sec) to maintain thickness. This dynamic cooling rate adjustment resolves the contradiction between achieving amorphous state and maintaining critical thickness.

Inventive Principle:

Principle #15Dynamics

2Length of stationary object

If slow cooling rates are used, then the critical thickness can be increased, but crystallization occurs and mechanical properties are lost

Engineering Contradiction:

ImprovethicknessVSAvoidmechanical properties

Core Design Contradiction:

Length of stationary objectVSStrength

Solution Approach 1:

The amorphous structure is formed first in the first region through rapid cooling before the material enters the second region. This preliminary action of forming the amorphous structure at high cooling rates ensures that the material has the desired mechanical properties before thickness maintenance is achieved in the second region.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Different regions of the cooling system provide different cooling rates tailored to local requirements. The first region provides high cooling rates to ensure amorphous formation and mechanical properties, while the second region provides controlled cooling rates to maintain sufficient thickness. This local quality approach allows simultaneous optimization of both parameters.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If conventional forming methods are used for high aspect ratio products, then production costs increase and mechanical properties are compromised

Engineering Contradiction:

Improveproduction costVSAvoidmechanical properties

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The invention changes the cooling rate parameter across different spatial regions to enable direct production of high aspect ratio products with maintained mechanical properties. By providing high cooling rates in the first region and controlled cooling rates in the second region, the process achieves both cost-effectiveness and property preservation, eliminating the need for expensive conventional forming methods.

Inventive Principle:

Principle #35Parameter changes

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

Enables the production of large-area amorphous BMG sheets with controlled amorphicity, maintaining mechanical properties and reducing production costs by effectively managing the cooling process to avoid crystallization.

Implementation Method 1

cooling the BMG sheet with a cooling fluid at a rate at which the BMG sheet remains amorphous after solidification

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

a heater configured to melt the BMG feedstock or to keep BMG in a molten state molten

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

spinning the stage at a speed sufficient to spread the BMG in a molten state on the spinning stage into a BMG sheet

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS9108243B2Production of large-area bulk metallic glass sheets by spinning

Publication Date: 2015.08.18 CRUCIBLE INTPROP LLC

AI summary

Disclosed herein is a device comprising: vacuum chamber; a stage configured to receive BMG in a molten state or a BMG feedstock, configured to spin, and located in the vacuum chamber; a heater configured to melt the BMG feedstock or to keep BMG in a molten state molten; wherein the stage comprises one or more conduits therein and the conduits are configured to accommodate a cooling fluid. Also disclosed herein is a method of forming a solid BMG sheet, the method comprising: disposing BMG in a molten state onto a stage; spreading the BMG in a molten state into a sheet of BMG in a molten state by spinning the stage; cooling the sheet of BMG in a molten state to form a solid BMG sheet.