Additive Ni-Cr-Mo Alloy Microstructure for Strength and Corrosion Resistance

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Solution Overview

Problem

Existing Ni-based alloys used in severe environments, such as chemical plants and semiconductor manufacturing, lack the necessary combination of high strength, hardness, and corrosion resistance, and are difficult to manufacture in complex shapes.

Innovation Solution

A Ni-based alloy with a composition including Ni, Cr, and Mo, featuring columnar cell structures with Mo segregation between adjacent cells, produced through additive manufacturing, and optimized by heat treatment and aging processes to enhance mechanical properties and corrosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional Ni-Cr-Mo based alloy is used to improve corrosion resistance, then corrosion resistance is improved, but mechanical properties (strength and hardness) are insufficient

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidmechanical properties

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention changes the microstructural parameters by controlling the segregation of Mo during additive manufacturing solidification. By optimizing the cooling rate and solidification conditions, Mo segregates to form intercellular regions with higher Mo concentration, which strengthens the alloy while maintaining corrosion resistance through the Ni-Cr-Mo composition system.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite microstructure at the cellular level, where cells with lower Mo concentration alternate with intercellular regions of higher Mo concentration. This cellular composite structure, formed during additive manufacturing, provides both high strength from the Mo-enriched boundaries and good corrosion resistance from the overall Ni-Cr-Mo composition.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional manufacturing methods (die forging or machine work) are used, then manufacturing process is simple, but complex shapes are difficult to manufacture

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidcomplex shape capability

Core Design Contradiction:

Ease of manufactureVSShape

Solution Approach 1:

The invention replaces conventional mechanical manufacturing methods (die forging, machine work) with additive manufacturing technology. This substitution enables the direct fabrication of complex three-dimensional shapes that are impossible to achieve through traditional mechanical processes, while maintaining manufacturing efficiency through automated layer-by-layer construction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Shape

If additive manufacturing is used to obtain complex shapes, then shape complexity is improved, but mechanical properties need further improvement

Engineering Contradiction:

Improvecomplex shape capabilityVSAvoidmechanical properties

Core Design Contradiction:

ShapeVSStrength

Solution Approach 1:

The invention optimizes additive manufacturing parameters including laser power, scanning speed, and layer thickness to control solidification conditions. By adjusting these parameters, the process achieves fine cellular structures with appropriate Mo segregation, resulting in improved mechanical properties while maintaining the ability to manufacture complex shapes.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates local variations in composition and microstructure through Mo segregation during solidification. The intercellular regions have higher Mo concentration providing local strengthening, while the cell interiors maintain the base Ni-Cr-Mo composition. This local quality variation enhances overall mechanical properties without compromising the complex shape capability of additive manufacturing.

Inventive Principle:

Principle #3Local quality

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 alloy achieves high tensile strength, hardness, and corrosion resistance, suitable for complex shapes, surpassing conventional manufacturing methods in mechanical properties and adaptability to harsh environments.

Implementation Method 1

the additive manufacturing method includes repeating an operation of melting a raw material powder by supplying a source of heat thereto and solidifying the melt to obtain a three-dimensional shape additively manufactured body

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

The Ni-based alloy member is an additively manufactured body and includes segregation of Mo in at least a part of a crystal grain(s)

Methodology Applied

Scientific EffectSegregation: Diffusion

Data Source

PatentUS12521794B2Ni-based alloy member including additively manufactured body, method for manufacturing Ni-based alloy member, and manufactured product using Ni-based alloy member

Publication Date: 2026.01.13 PROTERIAL LTD

AI summary

An additively manufactured body including a Ni—Cr—Mo based alloy that is excellent in mechanical properties. An additively manufactured body of the present invention is a member including a Ni-based alloy that includes Ni at the largest content by a mass ratio, and Cr and Mo at second largest contents by a mass ratio; and includes segregation of Mo in at least a part of a crystal grain(s). This crystal grain(s) has columnar cell structures (CL), and preferably the segregation of Mo exists between adjacent cell structures. A tensile strength of 850 MPa or higher and an elongation of 50% or higher can be obtained.