Study on Material Removal and Surface Characteristics of Thin-Walled Array Structure Regenerators Made of Rare-Earth Gadolinium: Magnetic Field-Assisted Wire Electrical Discharge Machining

Rare-earth gadolinium (Gd) is a preferred material for manufacturing room temperature magnetic refrigeration regenerators owing to its unique magnetocaloric properties. To enhance cooling performance, regenerators are often processed into complex thin-walled array structures. Achieving high precision, efficiency, and quality in the manufacturing of such components remains a significant challenge. Magnetic field-assisted wire electrical discharge machining (MF-WEDM) offers distinct advantages for fabricating high-precision components. This study develops a charged particle motion model and a material removal model to investigate the micro-discharge and material removal mechanisms in MF-WEDM. Additionally, a single discharge experiment indicates that the geometric dimensions of discharge craters vary with the magnetic field strength (BM). Single-factor experiments varying the BM parameter reveal that the material removal rate increases by 11.39%. At an optimal BM of 0.3 T, the recast layer (RL) thickness was reduced to 5.46 μm, microhardness decreased to 203.90 HV, and surface roughness (SR) was reduced by 18% compared to the non-magnetic field condition. Furthermore, based on the results of a Taguchi experiment, a regression model for discharge process parameters was established. Through analysis of variance, the significant effects of various parameters on SR and RL thickness were revealed.