Microstructure Control in Soldered Components via Magnetic Fields

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Solution Overview

Problem

Existing metallurgical processes such as soldering, welding, brazing, and casting struggle to control the size, orientation, and morphology of microstructures in metal parts, which affects their physical and mechanical properties, and often result in issues like residual stresses and 'tin whiskers' in lead-free solder joints.

Innovation Solution

Exposing low magnetic response metals to a relatively weak magnetic field during the metallurgical processes to influence the microstructure formation, using magnets with specific orientations and strengths to control grain sizes and orientations, and potentially adding alloying ingredients to enhance magnetic field effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional metallurgical processes (soldering, welding, brazing, casting) are used without magnetic field control, then the processes are simple and easy to manufacture, but the microstructure size, orientation, and morphology cannot be controlled, resulting in poor manufacturing precision

Engineering Contradiction:

Improvemicrostructure controlVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

A magnetic field is introduced as an intermediary agent during metallurgical processes to control microstructure formation. The magnetic field interacts with the molten metal to influence grain size, orientation, and morphology without requiring fundamental changes to the base process equipment, thereby achieving precise microstructure control while maintaining relative process simplicity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies magnetic field parameters (strength, orientation, duration) as controllable variables to influence metallurgical outcomes. By adjusting these magnetic parameters during soldering, welding, brazing, or casting, the microstructure properties can be precisely controlled without changing the fundamental nature of the metallurgical process

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If strong magnetic fields are used to control microstructure, then microstructure control is improved, but the energy consumption and equipment complexity increase significantly

Engineering Contradiction:

Improvemicrostructure controlVSAvoidenergy consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent demonstrates that relatively weak magnetic fields applied during specific critical phases of metallurgical processes are sufficient to achieve meaningful microstructure control. This partial action approach avoids the excessive energy consumption associated with strong continuous magnetic fields while still obtaining the desired microstructural outcomes

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The magnetic field is applied during the molten metal phase, before solidification completes, to influence microstructure formation during the critical transformation period. This preliminary action during the processing phase achieves control without requiring post-processing interventions or excessively strong fields

Inventive Principle:

Principle #10Preliminary action

3Reliability

If traditional soldering processes are used without magnetic field control, then the process is simple, but residual stresses and tin whiskers form in lead-free solder joints

Engineering Contradiction:

Improvesolder joint reliabilityVSAvoidsoldering process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A magnetic field serves as an intermediary during the soldering process to control the solidification of lead-free solder. This intermediary influence promotes uniform grain structure and reduces defects like tin whiskers and residual stresses without requiring complex modifications to the soldering equipment or process

Inventive Principle:

Principle #24Intermediary (Mediator)

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 predictable and repeatable control of microstructure properties, reducing residual stresses, inhibiting 'tin whiskers', and enhancing the shock and vibration tolerance of lead-free solders, while being applicable to various metallurgical processes including soldering, brazing, and casting.

Implementation Method 1

exposing at least a portion of the low magnetic response fused metal to a magnetic field

Methodology Applied

Scientific EffectMagnetic field effect on microstructure: Magnetic Field

Data Source

PatentUS9181611B2Control of microstructure in soldered, brazed, welded, plated, cast or vapor deposited manufactured components

Publication Date: 2015.11.10 CONSOLIDATED NUCLEAR SECURITY LLC

AI summary

Disclosed are methods and systems for controlling of the microstructures of a soldered, brazed, welded, plated, cast, or vapor deposited manufactured component. The systems typically use relatively weak magnetic fields of either constant or varying flux to affect material properties within a manufactured component, typically without modifying the alloy, or changing the chemical composition of materials or altering the time, temperature, or transformation parameters of a manufacturing process. Such systems and processes may be used with components consisting of only materials that are conventionally characterized as be uninfluenced by magnetic forces.