Cobalt Alloy Additive Manufacturing Carbide Precipitation
Solution Overview
Problem
Cobalt-based alloy materials used in additive manufacturing for high-temperature components exhibit inferior mechanical properties compared to precipitation-strengthened nickel-based alloy materials, primarily due to the lack of effective carbide phase precipitation, which limits their application in high-temperature environments.
Innovation Solution
A cobalt-based alloy composition with optimized carbide phase precipitation is achieved through selective laser melting, where specific transition metal carbides are dispersedly precipitated in the matrix phase crystal grains, improving mechanical properties by controlling alloy composition and heat input during the additive manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cobalt-based alloy materials are used in additive manufacturing for high-temperature components, then corrosion resistance and abrasion resistance are improved, but mechanical properties are inferior compared to nickel-based alloys
Solution Approach 1:
The invention changes the chemical composition parameters of the cobalt-based alloy by precisely controlling the content ranges of key elements (Cr: 10-30%, W: 3-15%, Mo: 3-15%, C: 0.05-0.30%, B: 0.05-0.20%, Ti: 0.5-2.0%, Zr: 0.5-2.0%, Hf: 0.5-2.0%, V: 0.5-2.0%, Nb: 0.5-2.0%, Ta: 0.5-2.0%, Al: 0.1-1.0%). This compositional optimization enables effective carbide phase precipitation while maintaining corrosion and abrasion resistance, thereby improving mechanical properties to be comparable with or exceed nickel-based alloys.
Solution Approach 2:
The invention creates a composite microstructure consisting of a cobalt-based matrix phase combined with dispersed carbide phases (MC, M2C, M3C, M6C, M7C, or M23C6 types). This composite structure integrates the excellent corrosion and abrasion resistance of the cobalt matrix with the strengthening effect of carbide precipitates, achieving mechanical properties comparable to nickel-based alloys while maintaining the inherent advantages of cobalt-based materials.
2Ease of manufacture
If conventional cobalt-based alloy compositions are used, then ease of manufacture is maintained, but carbide phase precipitation is insufficient, limiting mechanical property improvement
Solution Approach 1:
The invention optimizes manufacturing parameters including laser power (50-200 W), scanning speed (10-100 mm/s), hatch spacing (0.05-0.20 mm), and layer thickness (0.03-0.10 mm) to control heat input and cooling rate during additive manufacturing. These parameter changes promote effective carbide phase precipitation while maintaining process feasibility and ease of manufacture.
Solution Approach 2:
The invention develops a universal cobalt-based alloy composition and manufacturing parameter set that can be applied to additive manufacturing processes to achieve both effective carbide phase precipitation and good manufacturability. The optimized composition and parameters work together to enable successful production of high-temperature components with improved mechanical properties through standard additive manufacturing equipment and procedures.
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 cobalt-based alloy products demonstrate mechanical properties comparable to or exceeding those of precipitation-strengthened nickel-based alloys, including enhanced creep rupture time and high-temperature tensile strength, making them suitable for high-temperature applications.
Implementation Method 1
selective laser melting of a cobalt-based alloy powder to thereby obtain a dense three-dimensional article
Implementation Method 2
local melting and rapid solidification of the cobalt-based alloy powder
Implementation Method 3
specific transition metal carbides are dispersedly precipitated in the matrix phase crystal grains, improving mechanical properties by controlling alloy composition and heat input during the additive manufacturing process
Data Source
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AI summary
There is provided a cobalt-based alloy product comprising: in mass %, 0.08-0.25% C; 0.1% or less B; 10-30% Cr; 5% or less Fe and 30% or less Ni, the total amount of Fe and Ni being 30% or less; W and/or Mo, the total amount of W and Mo being 5-12%; 0.5% or less Si; 0.5% or less Mn; 0.003-0.04% N; 0.5 to 2 mass % of an M component being a transition metal other than W and Mo and having an atomic radius of more than 130 pm; and the balance being Co and impurities. The impurities include 0.5% or less Al and 0.04% or less O. The product is a polycrystalline body of matrix phase crystal grains. In the matrix phase crystal grains, segregation cells with an average size of 0.13-2 µm are formed, in which the M component is segregated in boundary regions of the segregation cells.