Titanium Shot Peening Media via Controlled Oxidation

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Solution Overview

Problem

Shot peening processes often result in surface contamination and increased roughness, particularly when using iron-based particles on corrosion-resistant alloys like aluminum and magnesium, which can degrade corrosion resistance, and existing ceramic media may introduce contamination when peening titanium alloys.

Innovation Solution

Producing peening media by subjecting titanium particles to a thermal process in an oxygen-containing atmosphere to increase surface hardness through solid solution strengthening without forming a distinct oxide layer, allowing them to be used as Ti-based shot peening media for titanium alloys, thus avoiding surface contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If iron-based particles are used as peening media, then the surface hardness of the particles is sufficient for peening, but surface contamination occurs and corrosion resistance deteriorates

Engineering Contradiction:

Improvesurface hardnessVSAvoidsurface contamination

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent uses titanium particles as peening media to match the base metal material, ensuring homogeneity between the peening media and the workpiece. This eliminates material incompatibility and prevents contamination, directly resolving the contradiction between achieving sufficient hardness and avoiding surface contamination.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The patent applies thermal processing parameters (temperature and time) to titanium particles to increase their surface hardness through controlled oxidation and phase transformation. This allows the particles to achieve the necessary hardness for effective peening while maintaining material compatibility with titanium alloys, thus resolving the contradiction between hardness and contamination.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If titanium particles are used as peening media, then surface contamination is avoided, but the surface hardness is insufficient for effective peening

Engineering Contradiction:

Improvesurface contaminationVSAvoidsurface hardness

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent employs specific thermal processing parameters (temperature range and holding time) to transform the microstructure of titanium particles and increase their surface hardness. This resolves the contradiction by enabling titanium particles to achieve sufficient hardness for effective peening while maintaining material compatibility and avoiding contamination.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes oxidation during thermal processing to increase the hardness of titanium particles. The controlled oxidation creates a harder surface layer on the particles, enabling them to effectivelypeen titanium alloys while maintaining material compatibility and avoiding contamination issues.

Inventive Principle:

Principle #38Strong oxidants (Accelerated oxidation)

3Strength

If thermal processing is applied to increase surface hardness, then an oxide layer forms that encases the particles, but this prevents effective peening

Engineering Contradiction:

Improvesurface hardnessVSAvoidpeening effectiveness

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent precisely controls thermal processing parameters (temperature and time) to achieve the desired surface hardness increase while preventing excessive oxide layer formation. By optimizing these parameters, the patent resolves the contradiction between increasing hardness and maintaining peening effectiveness.

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

The process significantly increases the surface hardness of titanium particles, enabling their use as effective shot peening media without introducing contaminants, thereby improving fatigue properties and maintaining corrosion resistance of titanium alloys.

Implementation Method 1

The particles are subjected to a thermal process in an oxygen-containing atmosphere at a process temperature and for a process duration sufficient to oxidize the surfaces of the particles to increase the surface hardness of the particles

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

at least surfaces of the particles are formed of or contain a metal that exhibits solubility for oxygen in a metallic phase so as to increase in surface hardness as a result of solid solution strengthening due to oxidizing of the surfaces of the particles

Methodology Applied

Scientific EffectSolid solution strengthening: Solid Solution Strengthening

Data Source

PatentUS11376712B2Peening media and processes for producing and using peening media

Publication Date: 2022.07.05 PURDUE RES FOUND

AI summary

Processes for producing peening media, the peening media produced from such processes, and methods of using such media. Particles are provided having surfaces that are formed of or contain a metal that exhibits solubility for oxygen in a metallic phase so as to increase in surface hardness as a result of solid solution strengthening due to oxidizing of the surfaces of the particles. The particles are subjected to a thermal process in an oxygen-containing atmosphere at a process temperature and for a process duration sufficient to oxidize the surfaces of the particles to increase the surface hardness of the particles while not forming an oxide layer that encases the particles.