Annealed Al-Si Sliding Material for Wear and Crack Balance

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Solution Overview

Problem

Existing aluminum alloys with high Si content for improved wear resistance suffer from non-homogeneous Si distribution, leading to localized hard regions that are prone to cracking under external forces, compromising the sliding characteristics of the material.

Innovation Solution

A sliding material comprising an aluminum alloy with Si content between 7.0 to 12.6 mass%, and a Si-rich region with a concentration of 17 mass% or more occupying 5% or more in area ratio, optimized through annealing conditions and controlled Si distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the amount of Si added to the aluminum alloy is increased to improve wear resistance, then wear resistance is improved, but the material becomes prone to cracking under external forces

Engineering Contradiction:
Improvewear resistanceVSAvoidcrack resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention creates a non-uniform Si distribution with distinct regions: Si-rich regions (≥17 mass% Si, 5% or more area ratio) that provide wear resistance, and Si-poor regions that maintain ductility and crack resistance. This local differentiation allows each region to perform its specific function optimally.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention controls the Si concentration parameter by establishing specific ranges: 7.0-12.6 mass% overall Si content in the alloy, and ≥17 mass% Si concentration in the Si-rich regions. These parameter specifications enable the material to achieve both wear resistance and crack suppression.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If Si is added to the aluminum alloy, then wear resistance is improved through formation of harder regions, but the Si distribution becomes non-homogeneous leading to localized hard regions

Engineering Contradiction:
Improvewear resistanceVSAvoidSi distribution homogeneity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention intentionally creates non-homogeneous Si distribution with distinct Si-rich and Si-poor regions. The Si-rich regions (≥17 mass% Si) provide wear resistance while the Si-poor regions maintain ductility, transforming the harmful non-homogeneity into a functional feature.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention creates a composite microstructure within the aluminum alloy, combining Si-rich hard regions and Si-poor softer regions. This internal composite structure allows the material to exhibit both wear resistance from the hard Si-rich phases and ductility from the Si-poor matrix.

Inventive Principle:
Principle #40Composite materials

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 solution provides enhanced wear resistance and crack suppression, ensuring suitable hardness and sliding performance for automotive bearings.

Implementation Method 1

the sliding material having undergone annealing for the aluminum alloy

Methodology Applied
Scientific EffectAnnealing: Annealing

Data Source

PatentEP4589038A1Sliding material
Publication Date: 2025.07.23 DAIDO METAL CO LTD
  • EP4589038A1 patent drawingFigure 1~2
  • EP4589038A1 patent drawingFigure 3A1~3B2
  • EP4589038A1 patent drawing

AI summary

A sliding material of the present invention includes an aluminum alloy added with Si, the sliding material having undergone annealing for the aluminum alloy, in which an amount of Si added is in a range from 7.0 to 12.6 mass%, and a Si-rich region having a Si concentration of 17 mass% or more present in a field of view of observation of the aluminum alloy accounts for 5% or more in area ratio.