Abstract The influence of hydroextrusion on structural changes in Invar high-carbon alloy 1N31 with a graphite component has been studied by metallography, microhardness measurements, and transmission electron microscopy. This process is accompanied by an almost twofold increase in microhardness up to a depth of 270–300 μm measured along scratches applied across the longitudinal section of the sample in the last cycle of the second hydrodynamic extrusion pass. It has been proved by means of transmission electron microscopy that the achieved strengthening of the near-surface layers is connected not only with additional solid-solution strengthening of austenite owing to a complete dissolution of the graphite component in it, but also with the extreme dispersion level of structural elements that form twin orientations in two mutually normal directions. The results are discussed in the scope of the model proposed earlier for the formation and features of the hydrodynamic state of the sample material in the course of hydrodynamic extrusion.

中文翻译：

---

流体动力挤压及其对因瓦 1N31 合金中石墨行为和结构形成的影响

摘要 通过金相、显微硬度测量和透射电子显微镜研究了水挤压对含石墨成分的因瓦高碳合金 1N31 结构变化的影响。该过程伴随着显微硬度几乎翻倍增加，深度为 270-300 μm，沿着在第二次流体动力挤压最后一个循环中施加在样品纵向截面上的划痕测量。透射电子显微镜已经证明，近表面层的强化不仅与奥氏体的额外固溶强化有关，因为其中的石墨成分完全溶解，但也有结构元素的极端分散水平，在两个相互法向的方向上形成双取向。结果在先前提出的模型范围内讨论，用于在流体动力挤出过程中样品材料的流体动力状态的形成和特征。