The paper considers one of the topical problems of the targeted control of the properties of the material of products in the zones under critical loads, which lead to their failure or loss of performance. The processes for the diffusion saturation of the surface layers of parts (chemical heat treatment) are an effective method for the strengthening treatment of parts of complex geometric shape. The ion-plasma thermocyclic nitriding technology developed by the Pisarenko Institute of Problems of Strength of the National Academy of Sciences of Ukraine is used for the treatment of specimens of ChS70VI heat-resistant alloy to study its effect on fatigue resistance characteristics. A technology for the ion-plasma thermocyclic nitriding of the surface of specimens and its conditions are presented. In the ion-plasma thermocyclic nitriding technology, heating is effected through glow discharge energy. In this case, the electrical power consumption is greatly reduced (by a factor of ~10) compared with similar chemical heat treatments. Micrographic investigations to determine the surface layer characteristics of specimens after ion-plasma thermocyclic nitriding are presented. The depth distributions of alloying and saturating elements in the specimen were obtained. The micrographic investigations showed that a fairly homogeneous layer 3 μm deep, uniformly distributed over the specimen surface, was formed after treatment by ion-plasma thermocyclic nitriding. To assess the influence of the above technological treatment of specimens, fatigue tests of these specimens and speciments in the initial state were carried out. It was shown that due to the strengthened layer formed on the test surface of specimens, the process of scattered damage accumulation under cyclic loading slows down, and the fatigue resistance characteristics improve: the endurance limit of specimens at the number of cycles to failure N = 10⁷ cycles after technological treatment is 32% higher than that of specimens in the initial state.

中文翻译：

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等离子热渗氮对ChS70VI合金疲劳强度的影响

本文考虑了在临界载荷下有针对性地控制区域内产品材料的性能的主题问题之一，这导致其失效或性能下降。零件表面层扩散饱和的过程（化学热处理）是一种增强处理复杂几何形状零件的有效方法。乌克兰国家科学院Pisarenko强度问题研究所开发的离子等离子体热循环渗氮技术用于处理ChS70VI耐热合金试样，以研究其对耐疲劳特性的影响。提出了一种用于标本表面离子等离子体热渗氮的技术及其条件。在离子等离子体热循环氮化技术中，通过辉光放电能量进行加热。在这种情况下，与类似的化学热处理相比，功耗大大降低（约10倍）。进行了显微照片研究，以确定离子-等离子体热循环氮化后的样品表面层特性。得到了试样中合金元素和饱和元素的深度分布。显微照片研究表明，经过离子等离子体热循环氮化处理后，形成了一个均匀的3μm深的均匀层，均匀分布在样品表面上。为了评估上述试样的技术处理的影响，对这些试样和初始状态的试样进行了疲劳测试。技术处理后的⁷个循环比初始状态下的样本高32％。