Using thermochemical treatments, boronized layers were successfully prepared on Al_0.25CoCrFeNi high-entropy alloys (HEAs). The thickness of the boronized layers ranged widely from 20 to 50 µm, depending on the heat treatment time. Boronizing remarkably improved the surface hardness from HV 188 to HV 1265 after treating at 900°C for 9 h. Moreover, boronizing enhanced the yield strength of HEAs from 195 to 265 MPa but deteriorated the tensile ductility. Multiple crackings in the boride layers significantly decreased the plasticity. The insufficient work-hardening capacity essentially facilitated the plastic instability of the boronized HEAs. With decreasing substrate thickness, the fracture modes gradually transformed from dimples to quasi-cleavage and eventually to cleavage.

通过热化学处理，成功在Al _0.25 CoCrFeNi高熵合金（HEAs）上制备了硼化层。取决于热处理时间，硼化层的厚度在20至50 µm的宽范围内变化。硼化处理在900°C下处理9小时后，表面硬度从HV 188显着提高到HV 1265。此外，渗硼使HEA的屈服强度从195 MPa提高到265 MPa，但拉伸延展性下降。硼化物层中的多次裂纹显着降低了可塑性。不足的加工硬化能力实质上促进了硼化HEA的塑性不稳定。随着基底厚度的减小，断裂模式逐渐从酒窝转变为准劈裂，最终转变为劈裂。