Layered In-Situ Metal Matrix Composites for Wear Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ferrous metal coatings used for wear resistance in applications like drill pipes and boiler tubes face cracking issues due to low toughness and substrate limitations, making layer-by-layer construction of freestanding parts challenging, and aggressive heat treatments like quenching and tempering lead to yield loss and distortion.
Innovation Solution
A method of layer-by-layer construction using alloys with at least 50% Fe, B, Cr, Si, and Ni, with optional C and Mn, that forms a primary dendritic austenite phase and small interdendritic lamellar boride phases, which are then heat-treated to grow spheroidized boride phases, enhancing wear resistance and toughness without requiring quenching or tempering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ferrous metal coatings are increased in thickness to provide wear resistance, then wear resistance is improved, but the coatings crack due to low toughness
Solution Approach 1:
The invention uses a composite material system consisting of austenite matrix with embedded carbide and boride phases. The austenite matrix provides toughness and ductility, while the hard carbide and boride phases provide wear resistance. This composite structure allows the coating to maintain both high wear resistance and adequate toughness, preventing cracking even at increased thicknesses.
Solution Approach 2:
The invention changes the chemical composition parameters by adding specific elements (B, Cr, Mo, Ni) to the ferrous alloy system. These compositional changes promote the formation of austenite matrix with dispersed carbide and boride phases during solidification, transforming the material properties to achieve both wear resistance and toughness simultaneously.
2Reliability
If aggressive heat treating processes like quench and temper are applied to achieve high wear resistance, then wear resistance is improved, but yield loss and part distortion increase
Solution Approach 1:
The desired microstructure (austenite matrix with carbide and boride phases) and properties (wear resistance and toughness) are achieved during the layerwise construction solidification process itself, rather than requiring subsequent aggressive heat treatment. This preliminary formation of the optimal microstructure eliminates the need for quenching and tempering, thereby avoiding yield loss and part distortion.
Solution Approach 2:
The invention replaces the mechanical/thermal stress-based heat treatment process (quench and temper) with a controlled solidification process that directly forms the desired microstructure. Instead of using aggressive thermal cycling to achieve wear resistance, the process uses controlled cooling rates during layerwise construction to precipitate the hard phases in situ, substituting a gentler process that avoids distortion.
3Adaptability or versatility
If layerwise construction is used to build freestanding parts, then component freedom is improved, but cracking occurs due to substrate limitations
Solution Approach 1:
The invention changes the material parameters by using a ferrous alloy composition specifically designed for layerwise construction, containing B, Cr, Mo, and Ni elements. These compositional changes ensure that during the layerwise construction process, the material forms an austenite matrix with dispersed carbide and boride phases, achieving both freestanding component capability and crack-free integrity.
Solution Approach 2:
The composite microstructure of austenite matrix with embedded hard phases provides both the ductility needed for freestanding component formation and the toughness to prevent cracking during layerwise construction. The hard carbide and boride phases are distributed throughout the matrix, providing crack resistance while allowing the component to be built as a freestanding structure.
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 method produces free-standing metallic parts with high wear resistance and toughness, as measured by ASTM G65-04 Procedure A, with improved abrasion resistance and ductility, and heat treatment increases tensile elongation and impact toughness, avoiding cracking and distortion.
Implementation Method 1
cooling and forming a solidified layer wherein each of the solid layers has a thickness as formed of 5.0 to 200.0 microns. The solidified layer after cooling includes the identified elements defining a primary dendritic austenite phase and an initial level of relatively small interdendritic lamellar boride phases
Implementation Method 2
upon heating, the interdendritic lamellar boride phases consolidate and grow including by diffusion of elements from the primary phase into relatively small spheroidized (sphere-like shape) boride phases
Data Source
AI summary
The present disclosure is directed at alloys and method for layer-by-layer deposition of metallic alloys on a substrate to produce a metallic part. Applications for the metallic parts include pumps, pump parts, valves, molds, bearings, cutting tools, filters or screens.