X-ray Target Aligned Grain Structure Thermal Stress

Solution Overview

Problem

X-ray tubes face failure due to cyclical thermal stress causing the target material to crack or delaminate from the mounting surface, leading to structural integrity issues under high temperatures.

Innovation Solution

A target material with an aligned grain structure is used, where the major axis of the grains is oriented perpendicular to the mounting surface, increasing the number of grains per unit area at the interface and enhancing resistance to thermal cycling, thereby reducing the likelihood of delamination and cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the target material is subjected to cyclical thermal stress during operation, then the target generates x-rays in response to incident electrons, but the target material cracks and/or separates from the mounting surface leading to failure

Engineering Contradiction:

Improvex-ray generation capabilityVSAvoidtarget structural integrity

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent applies local quality by creating a non-uniform grain structure where grains are deliberately elongated in the thickness direction (perpendicular to the mounting surface). This localized structural modification at the grain level enhances thermal stress resistance specifically at the interface between the target material and mounting surface, while maintaining the overall x-ray generation capability of the target.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of grain structure morphology by controlling the elongation of grains in the thickness direction. This parameter change in the microstructure transforms the target material's response to thermal cycling, reducing thermal stress accumulation and preventing delamination while preserving the material's ability to generate x-rays under electron bombardment.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the target material uses materials like tungsten or tungsten-rhenium to improve strength under thermal stress, then the target material strength increases, but thermal stress still causes cracking and delamination

Engineering Contradiction:

Improvetarget material strengthVSAvoidresistance to thermal cycling

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies local quality by creating a non-uniform grain structure where grains are deliberately elongated in the thickness direction (perpendicular to the mounting surface). This localized structural modification at the grain level enhances thermal stress resistance specifically at the interface between the target material and mounting surface, while maintaining the overall x-ray generation capability of the target.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of grain structure morphology by controlling the elongation of grains in the thickness direction. This parameter change in the microstructure transforms the target material's response to thermal cycling, reducing thermal stress accumulation and preventing delamination while preserving the material's ability to generate x-rays under electron bombardment.

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 aligned grain structure improves the target's resistance to thermal cycling, enhancing the reliability and longevity of the x-ray system by maintaining structural integrity and efficient heat dissipation.

Implementation Method 1

The target material may be subjected to cyclical thermal stress during operation. The target material may crack and/or separate from a mounting surface within the x-ray tube due to the thermal stress

Methodology Applied

Scientific EffectThermal stress: Thermal Expansion

Data Source

PatentUS20210193426A1Aligned grain structure targets, systems, and methods of forming

Publication Date: 2021.06.24 VAREX IMAGING CORP

AI summary

Some embodiments include an x-ray system, comprising: a support structure including a mounting surface; a target attached to the support structure on the mounting surface; wherein the target has a grain structure having a first dimension along an axis perpendicular to the mounting surface is longer than a longest dimension along any axis parallel to the mounting surface.