Low-Cobalt Alloy Maintains Hardness at 900°C
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Solution Overview
Problem
Conventional cobalt-based superalloys face challenges due to high costs and environmental concerns related to cobalt mining, limiting their practical applications and requiring improved mechanical characteristics for high-temperature applications.
Innovation Solution
A high hardness and temperature-resistant alloy with a composition of 10-40 atomic percent Co, 30-56 atomic percent Cr, 10-40 atomic percent Ni, 6-13 atomic percent C, and 0-8 atomic percent Mo, optionally including additive elements, which maintains hardness greater than HV100 at 900°C, suitable for processing into various articles like hot working tools and turbine blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional cobalt-based superalloy is used to achieve high-temperature mechanical strength, then excellent high-temperature performance is obtained, but high cost and environmental concerns arise due to expensive cobalt and over-mining issues
Solution Approach 1:
The patent changes the compositional parameters by reducing cobalt content from conventional levels (typically 60-70 at%) to 10-40 at%, while adjusting chromium (30-56 at%), nickel (10-40 at%), carbon (6-13 at%), molybdenum (0-8 at%), and tungsten (0-8 at%) to achieve the desired high-temperature mechanical strength at lower cost
Solution Approach 2:
The patent creates a composite alloy system combining multiple elements (Co, Cr, Ni, C, Mo, W) in specific proportions to achieve synergistic effects where chromium provides strength, nickel enhances ductility, and carbon forms strengthening precipitates, replacing conventional high-cobalt formulations
2Strength
If cobalt content is increased to maintain high-temperature performance, then excellent mechanical properties at high temperature are achieved, but environmental impact and resource sustainability deteriorate due to over-mining
Solution Approach 1:
The patent fundamentally changes the cobalt content parameter from conventional high levels to a reduced range of 10-40 at%, combined with optimized chromium (30-56 at%) and nickel (10-40 at%) content, to achieve the same high-temperature mechanical strength with reduced environmental impact from cobalt mining
3Ease of manufacture
If alloy composition is adjusted to reduce cost by decreasing cobalt content, then production cost is reduced, but maintaining high-temperature mechanical strength becomes difficult
Solution Approach 1:
The patent optimizes multiple compositional parameters simultaneously: chromium content (30-56 at%) for strength, nickel content (10-40 at%) for ductility, carbon content (6-13 at%) for precipitate formation, and limited Mo (0-8 at%) and W (0-8 at%) for hardening, achieving cost reduction through lower cobalt while maintaining high-temperature mechanical strength
Solution Approach 2:
The patent develops a composite alloy system where chromium provides primary strength contribution, nickel enhances high-temperature ductility, carbon forms strengthening precipitates (e.g., Cr23C6), and Mo/W provide solid solution strengthening, creating synergistic effects that maintain mechanical strength at reduced cobalt content
4Adaptability or versatility
If conventional superalloy composition is used to achieve adjustable mechanical characteristics, then various application requirements can be met, but price flexibility is limited due to expensive cobalt cost
Solution Approach 1:
The patent enables adjustable mechanical characteristics through multiple independent compositional parameters: chromium content (30-56 at%) for strength control, nickel content (10-40 at%) for ductility control, carbon content (6-13 at%) for precipitate control, and Mo/W content (0-8 at% each) for hardening control, providing price flexibility by reducing cobalt to 10-40 at%
Data Source
AI summary
A high hardness and temperature-resistant alloy is disclosed, and comprises 10-40 atomic percent Co, 30-56 atomic percent Cr, 10-40 atomic percent Ni, 6-13 atomic percent C, 0-8 atomic percent Mo, and 0-8 atomic percent W. Moreover, the elemental composition of the high hardness and temperature-resistant alloy can further comprise at least one additive element, such as Pb, Sn, Ge, Si, Zn, Sb, P, B, Mg, Mn, V, Nb, Ti, Zr, Y, La, Ce, Al, Ta, Cu, and Fe. Experimental data reveal that, the high hardness and temperature-resistant alloy can still show a property of hardness greater than HV100 in 900 degrees Celsius. Therefore, experimental data have proved that the high hardness and temperature-resistant alloy has a significant potential for applications in the manufacture of hot working die metals, components (e.g., turbine blade) for high temperature applications, and devices (e.g., aeroengine) for high temperature applications.