Metal Solid Bonding via Liquid Alloy Extraction Under Pressure

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Solution Overview

Problem

The bonding between Fe and Mg results in a low bond strength due to the formation of a large amount of brittle intermetallic compound Mg2Ni when the Fe100−xNix layer contains a sufficient amount of Ni (x>30), leading to a decrease in bond strength on the bonding face.

Innovation Solution

A method involving the interdiffusion of a first component and a third component with positive and negative heats of mixing, where a liquid alloy is generated and discharged under pressure to enhance bond strength, forming a co-continuous structure with finely intertangled components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a sufficient amount of Ni is contained in the Fe100−xNix layer to enable interdiffusion with Mg, then bonding between Fe and Mg is achieved, but a large amount of brittle intermetallic compound Mg2Ni is formed, resulting in low bond strength on the bonding face

Engineering Contradiction:

Improvebond strengthVSAvoidformation of brittle intermetallic compound

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The harmful liquid alloy (Mg-Ni eutectic mixture) is extracted from the bonding interface by applying pressure during heat treatment. This causes the liquid alloy to be discharged from the contact face, preventing its solidification into brittle intermetallic compounds and eliminating the harmful effect while maintaining the beneficial interdiffusion process

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The physical state of the Mg-Ni system is changed from solid to liquid by controlling the heat treatment temperature to match the eutectic point (709°C). This phase change enables high-speed liquid-phase diffusion, improving bonding while allowing the liquid alloy to be discharged under pressure, preventing brittle compound formation

Inventive Principle:

Principle #35Parameter changes

2Strength

If heat treatment is performed at high temperature for a long time to achieve sufficient interdiffusion, then bonding between immiscible metals is achieved, but the bonding time increases and energy consumption increases

Engineering Contradiction:

Improvebond strengthVSAvoidbonding time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The bonding process utilizes the eutectic phase transition of the Mg-Ni system at 709°C, where the solid components transform into a liquid alloy. This liquid-phase diffusion occurs much faster than solid-state diffusion, significantly reducing the required bonding time while achieving sufficient interdiffusion and bond strength

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The slow solid-state diffusion process is replaced by rapid liquid-phase diffusion through the eutectic reaction. The liquid alloy formed at the eutectic temperature provides high mobility for atomic interdiffusion, replacing the time-consuming mechanical diffusion process with a faster phase-change-driven process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method improves bond strength and ductility by preventing the solidification of the liquid alloy, allowing for a shorter bonding time and reduced heating temperatures, effectively bonding metals that are normally difficult to join.

Implementation Method 1

the first component and the third component interdiffuse (for example, see Patent Literature 1)

Methodology Applied

Scientific EffectInterdiffusion: Diffusion

Implementation Method 2

the first component (Mg) of the metal body and the third component (Ni) of the metal member (FeNi) were eutectically reacted with each other by a heat treatment to melt the contact face to generate a liquid containing the first and third components (Mg—Ni liquid)

Methodology Applied

Scientific EffectEutectic reaction: Phase Change

Implementation Method 3

heated at a predetermined temperature for a predetermined time while applying a predetermined pressure between the metal body and the metal material, so that the first component and the third component are interdiffused with each other, and a liquid alloy containing the first component and the third component, which has been generated in a region where the first component and the third component have interdiffused with each other, is discharged

Methodology Applied

Scientific EffectPressure-driven flow: Pressure Gradient

Data Source

PatentUS20260077577A1Method for manufacturing metal solid-to-metal solid bonded body, and composite member

Publication Date: 2026.03.19 TOHOKU UNIV

AI summary

A method for manufacturing a metal solid-to-metal solid bonded body, capable of improving a bond strength on a bonding face, and a composite member. A solid metal body containing a first component is brought into contact with a solid metal material composed of a compound, an alloy, or a non-equilibrium alloy, which contains both a second component and a third component having positive and negative heats of mixing respectively relative to the first component, and heated at a predetermined temperature for a predetermined time while applying a predetermined pressure to between the metal body and the metal material. Thereby, the first component and the third component are interdiffused with each other, and a liquid alloy containing the first component and the third component, which has been generated in a region where the first component and the third component have interdiffused with each other, is discharged.