# Identifying Optimal Processing Variables and Investigating Mechanisms of Grain Alignment in Hot-Deformed NdFeB Magnets through Design of Experiments

## TL;DR

This paper presents a new method to improve the magnetic properties of hot-deformed NdFeB magnets by optimizing processing variables and grain alignment.

## Contribution

The novel integration of MSDP and DoE methodology to enhance crystallographic alignment in NdFeB magnets is introduced.

## Key findings

- A hot-pressing temperature of 700 °C is critical for optimal grain alignment in NdFeB magnets.
- Adjusting the strain rate to 0.019 mm/s under 110 MPa stress significantly improves magnetic alignment.
- The combined MSDP and DoE approach successfully enhances remanence and coercivity in fabricated magnets.

## Abstract

This study introduces a novel approach for investigating hot-deformed NdFeB magnets by combining the minimal stress deformation process (MSDP) with the design of experiment (DoE) methodology. This study focused on enhancing the crystallographic alignment, particularly the c-axis alignment of the Nd2Fe14B grains, to optimize the magnetic properties. By utilizing the Box-Behnken design matrix and response surface regression, critical processes and variables were identified, determining that a hot-pressing temperature of 700 °C is crucial for achieving optimal grain alignment. Changing the strain rate to 0.019 mm/s under a stress of 110 MPa led to significant enhancements in the alignment, yielding magnets with a remanence of approximately 13.4 kG and a coercivity of 21 kOe. These findings highlight the effectiveness of combining the MSDP and DoE for predicting and achieving improved magnetic properties. Despite the challenges associated with understanding the complexity of crystal alignment mechanisms, this integrated approach successfully improved magnetic characteristics. The methodology represents a significant advancement in the fabrication of high-performance hot-deformed NdFeB magnets, marking a notable contribution to the field.