High entropy alloys (HEAs) are a novel subset of metallic systems with complex compositions usually yielding simple phase formation. To verify their potential engineering applications, a novel Co₁₆Fe₂₈Ni₂₈Cr₂₈ HEA with a low content of expensive Co was developed and its welding characteristics through friction-stir welding (FSW) were investigated. The HEA shows a stable face-centered-cubic (FCC) structure with an excellent ductility of about 70%. The microstructural evolution during FSW was dominated by discontinuous recrystallization through grain bulging and the B/$\overline{\mathrm{B}}$ {112}<110> shear texture formed in the stir zone (SZ). A white band (WB) containing W-rich and Cr-rich phases was detected in the SZ. The WB exhibited refined grains compared with the normal SZ, which may be associated with the particle-stimulated nucleation (PSN). The present understanding of the microstructural evolution during FSW of HEAs may help tailor the weld properties to pave the way for their engineering applications.

高熵合金（HEA）是金属系统的一个新子集，具有复杂的成分，通常会形成简单的相。为了验证其潜在的工程应用，开发了一种新型的Co ₁₆ Fe ₂₈ Ni ₂₈ Cr ₂₈ HEA，该合金具有低廉的昂贵Co含量，并研究了其通过搅拌摩擦焊（FSW）的焊接特性。HEA显示稳定的面心立方（FCC）结构，具有约70％的出色延展性。FSW期间的微观组织演变主要是由于晶粒凸起和B /$\overline{\mathrm{乙}}${112} <110>在搅拌区（SZ）中形成的剪切织构。在SZ中检测到包含W和Cr富集的白带（WB）。与正常的SZ相比，WB显示出细化的晶粒，这可能与颗粒刺激形核（PSN）有关。目前对HEA的FSW过程中微观结构演变的了解可能有助于定制焊接性能，为其工程应用铺平道路。