Oxide-Particle Dispersion Steel for Nuclear Cladding
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Solution Overview
Problem
Conventional zirconium alloys used in nuclear reactor cladding materials have a low accident tolerance rate, leading to hydrogen explosions under high temperature water vapor, which is a significant safety concern, and existing oxide-particles dispersion steels (ODS) offer high strength but poor plasticity, making them unsuitable for advanced reactors.
Innovation Solution
A high strength-ductility matched oxide-particles dispersion steel is developed with a specific composition and a preparation method involving pre-alloyed powders, ball milling, hot isostatic pressing, two-step forging, and heat treatment to introduce high-density, core-shell structured oxide particles, enhancing both strength and toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional zirconium alloy is used as cladding material, then excellent service performance is achieved, but accident tolerance rate is low and hydrogen explosion risk occurs
Solution Approach 1:
The patent develops oxide-dispersion strengthened (ODS) steel, a composite material combining iron-based matrix with dispersed oxide particles (Y2O3, SiO2, Cr2O3). This composite structure provides both high strength and improved accident tolerance by eliminating hydrogen embrittlement risks associated with zirconium alloys while maintaining structural integrity under reactor conditions.
2Object-affected harmful factors
If ODS steel is used to improve accident tolerance, then high strength is achieved, but plasticity is poor
Solution Approach 1:
The patent creates a dual-phase microstructure with martensite lath structure containing dispersed oxide particles. The martensite provides high strength while the oxide particles act as stress concentrators that prevent crack propagation. The local composition is optimized with specific ranges of Cr (11-13%), W (1-2%), V (0.1-0.2%), and Y (0.3-0.4%) to balance strength and ductility.
Solution Approach 2:
The patent employs precise control of processing parameters including heat treatment temperature (950-1150°C), holding time (10-30 minutes), and cooling rate to transform the microstructure. The heat treatment parameters are optimized to achieve tempered martensite structure with appropriate carbide precipitation, thereby improving plasticity while maintaining high strength.
3Reliability
If high chromium content is added to improve corrosion resistance, then corrosion resistance is enhanced, but carbide precipitation occurs reducing strength
Solution Approach 1:
The patent optimizes chromium content to a specific range (11-13%) and controls heat treatment parameters (temperature 950-1150°C, time 10-30 minutes) to prevent excessive carbide precipitation. The controlled chromium level provides sufficient corrosion resistance while the precise heat treatment parameters ensure carbides remain fine and dispersed, maintaining tensile strength above 1200 MPa.
Solution Approach 2:
The patent creates a multi-element composite system where Cr, W, and V work synergistically. Chromium provides corrosion resistance, tungsten contributes to solid solution strengthening, and vanadium refines the grain structure. This composite alloying strategy achieves corrosion resistance without sacrificing strength through carbide formation.
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 resulting steel exhibits improved tensile strength and plasticity at both room and high temperatures, meeting the requirements for nuclear reactor fuel cladding materials and offering enhanced safety and commercial value.
Implementation Method 1
The high-density dispersed ultra-fine oxide particles in ODS steels not only increase the strength but also have the properties of trapping irradiation defects and suppressing irradiation damage
Implementation Method 2
By introducing oxide-particles with a high density and a complete core-shell structure using a special heat treatment step
Implementation Method 3
preparing pre-alloyed powders using alloy components of Cr, W, V and Fe according to a proportion, then mixing with Si powder, Y powder and Y2O3 powder, followed by ball milling
Implementation Method 4
the sintering adopts a hot isostatic pressing sintering process
Implementation Method 5
the quenching is carried out under a temperature of 20°C
Data Source
AI summary
Disclosed are a high strength-ductility matched oxide-particles dispersion steel, a preparation method and application thereof, belonging to the technical field of novel structural materials. The high strength-ductility matched oxide-particles dispersion steel comprises the following components in percentage by mass: chromium (Cr) 11.0-13.0 percent (%), tungsten (W) 1.0-2.0%, vanadium (V) 0.1-0.2%, yttrium (Y) 0.3-0.4%, oxygen (O) 0.05-0.15%, silicon (Si) 1.5-2.5%, carbon (C) ≤0.0016%, with iron (Fe) and unavoidable impurities accounting for a rest. The high strength-ductility matched oxide-particles dispersion steel in the present application is prepared, using a powder metallurgical preparation method, by introducing high-content of silicon elements and introducing high-density oxide particles with a complete core-shell structure using a specific heat treatment regime.