Ni-base Alloy Nitride Size Control for Fatigue Strength
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Solution Overview
Problem
Existing Ni-base alloys used in aircraft and gas turbines face challenges in achieving stable fatigue strength due to the difficulty in evaluating and controlling the maximum particle diameter of nitrides, which affects their mechanical properties, and existing methods are not effective in predicting nitride sizes accurately.
Innovation Solution
A method is developed to calculate the area-equivalent diameter of nitrides in multiple fields of view, plotting these values to obtain a regression line that estimates the maximum nitride size, ensuring it remains below 25 μm, thereby improving the mechanical properties of the alloy by precise evaluation and control of nitride sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the nitrogen amount is reduced to prevent nitride formation, then fatigue strength should improve, but it is difficult to stably obtain sufficient fatigue strength without controlling nitride particle size
Solution Approach 1:
The patent replaces traditional visual observation methods with automated image processing and computer-based analysis to measure nitride particle sizes. This substitution enables precise, objective measurement of particle diameters, resolving the contradiction between improving fatigue strength and achieving accurate particle size evaluation.
Solution Approach 2:
The patent changes the measurement parameter from qualitative visual assessment to quantitative automated image analysis. By converting particle size evaluation into measurable digital parameters through image processing, the system achieves both improved fatigue strength control and precise particle size measurement.
2Ease of manufacture
If traditional visual observation methods are used to measure nitride particles, then the process is simple, but it is difficult to accurately grasp the maximum particle diameter
Solution Approach 1:
The patent replaces manual visual observation with automated image processing systems that capture, process, and analyze nitride particle images computationally. This substitution maintains operational simplicity while dramatically improving measurement accuracy for maximum particle diameter determination.
Solution Approach 2:
The patent creates digital copies of nitride particles through image capture and processing. These digital replicas allow for precise measurement and analysis without disturbing the actual particles, enabling accurate maximum diameter measurement while keeping the process straightforward.
3Strength
If the Ni-base alloy contains various phases, then the alloy achieves desired mechanical properties, but analysis of emission intensities and observation of nonmetallic inclusions cannot be performed in the same manner as in iron and steel
Solution Approach 1:
The patent applies localized image processing techniques that adapt to different phase characteristics within the multi-phase Ni-base alloy. By treating different regions and phases with appropriate analysis methods, the system overcomes the complexity of measuring nonmetallic inclusions in heterogeneous materials while maintaining overall mechanical property optimization.
Data Source
AI summary
In a Ni-base alloy, an area-equivalent diameter D is calculated. D is defined by D=A1/2 from an area A of a largest nitride in a field of view when an observation area S0 is observed. This process is repeated in n fields of view for measurement, where n is the number of the fields of view for measurement, so as to acquire n pieces of data on D, and the pieces are arranged in ascending order D1, D2, . . . , Dn to obtain a reduced variate yj. The obtained values are plotted on X-Y axis coordinates, where an X axis corresponds to D and a Y axis corresponds to yj. In a regression line yj=a×D+b, yj is obtained when a target cross-sectional area S is set to 100 mm2. When the obtained yj is substituted into the regression line, the estimated nitride maximum size is ≦25 μm in diameter.