Abstract

The processes of modifying the surface properties of 3Cr2V8F and 5CrNM tool steels by electron-beam alloying (EBA) in vacuum with boron and aluminum treatment mixtures are considered. Metallographic analysis of the cross sections showed that as a result of EBA, uniform layers with a high roughness and without visible signs of zoning (layering) with a thickness of up to ~500 μm are formed. The modified layers have a distinct boundary with the base metal. The crystallization process starts after the end of electron-beam heating; Thus, a dendrite-like structure of the modified layer is formed. An increase in the microhardness from 350 to 1550 HV occurred in the surface zone of the layer due to phase and structural transformations from the liquid state (X-ray phase analysis revealed the presence of Fe₂B, Fe₃Al, FeAl₃, AlB₂, and AlFe₂B₂ phases). Thermal stresses develop, contributing to the hardening and plastic deformation processes. Wave oscillations of the microhardness profiles are observed over the modified-layer thickness. It is established that the maximum microhardness after two-component (B₄C + Al) alloying is higher than after alloying with only boron carbide.

中文翻译：

---

3Cr2V8F 和 5CrNM 模具钢在真空中使用 B4C 和 Al 处理膏进行电子束表面合金化

摘要

考虑了在真空中用硼和铝处理混合物通过电子束合金化 (EBA) 改变 3Cr2V8F 和 5CrNM 工具钢的表面性能的过程。横截面的金相分析表明，作为 EBA 的结果，形成了具有高粗糙度的均匀层，并且没有可见的分区（分层）迹象，厚度高达 ~500 μm。改性层与基底金属有明显的边界。电子束加热结束后开始结晶过程；因此，形成了改性层的树枝状结构。由于液态的相和结构转变，层的表面区域的显微硬度从 350 HV 增加到 1550 HV （X 射线相分析显示 Fe 的存在）₂ B、Fe ₃ Al、FeAl ₃、AlB ₂和AlFe ₂ B ₂相）。热应力发展，促成硬化和塑性变形过程。在改性层厚度上观察到显微硬度分布的波动。确定双组分（B ₄ C + Al）合金化后的最大显微硬度高于仅与碳化硼合金化后的最大显微硬度。