Additively Manufactured Nd-Fe-B Magnet Buffer Layers for Crack Resistance
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Solution Overview
Problem
Existing methods for manufacturing permanent magnets, such as rare earth magnets, face challenges in enhancing mechanical properties and alleviating stresses that can lead to cracking, while maintaining magnetic performance.
Innovation Solution
The use of additive manufacturing techniques to create a permanent magnet with a magnetic phase and a buffer segment, where the buffer segment is composed of alloys like nickel, iron, cobalt, chromium, titanium, molybdenum, copper, or niobium, and their combinations, which are strategically layered to improve mechanical properties and reduce stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If additive manufacturing is used to manufacture permanent magnets, then manufacturing flexibility and customization are improved, but cracking and mechanical reliability deteriorate
Solution Approach 1:
The patent applies composite materials by combining magnetic alloy powder with buffer alloy powder in specific weight ratios (buffer alloy 10-40% by weight). The buffer alloy contains elements like Ni, Al, Fe, Co, Cr, Ti, Mo, Cu, or Nb that prevent cracking during additive manufacturing. This composite approach maintains manufacturing flexibility while significantly improving crack resistance and mechanical reliability of the permanent magnet.
2Reliability
If buffer alloy is added to improve mechanical properties, then crack resistance is improved, but magnetic performance deteriorates
Solution Approach 1:
The patent applies local quality by strategically distributing buffer alloy material within the magnetic structure rather than uniformly throughout. The buffer alloy is positioned to specifically address stress concentration zones and crack-prone regions during additive manufacturing, while leaving the magnetic phases intact to maintain magnetic performance. This localized approach ensures crack resistance improvement without significant loss of magnetic properties.
3Stability of the object's composition
If stratified layers are used to reduce stress, then mechanical stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the permanent magnet into alternating layers of magnetic alloy and buffer alloy, with each layer comprising 10-40% by weight of the total composition. This stratified structure is achieved through the additive manufacturing process by sequentially depositing different powder mixtures. The segmented layers effectively reduce internal stress and improve mechanical stability while the additive manufacturing process inherently manages the layering complexity.
Data Source
AI summary
A permanent magnet formed by additively manufacturing magnetic phases and buffer phases is disclosed. The buffer phase(s) may improve performance, enhance mechanical properties and allow the magnet to better tolerate stresses such that defects such as cracking do not occur or are less likely to occur. The buffer phase may be a magnetic or non-magnetic material.