Precipitation Behavior of IN718 After Surface Mechanical Attrition Treatment (SMAT) and Its Effect on Wear Properties
Precipitation Behavior of IN718 After Surface Mechanical Attrition Treatment (SMAT) and Its Effect on Wear Properties
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DOI：
10.1007/s11837-018-3134-3
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发表时间：
2018-11-01
期刊：
影响因子：
2.6
通讯作者：
Suwas, Satyam
中科院分区：
文献类型：
--
作者：
Bisht, Anuj;Gaddam, Supreeth;Suwas, Satyam
Inconel 718是一种沉淀强化的镍基高温合金，可在宽温度范围内（高达650摄氏度）应用。它具有优异的屈服强度、延展性、抗蠕变性和疲劳强度。已知表面处理通过表面层的纳米结晶来提高材料的疲劳寿命。然而，表面处理层的沉淀行为在很大程度上是未开发的。在这方面，本研究的目的是调查和比较的沉淀在表面处理层和本体溶液处理的IN718。材料在固溶处理后进行表面机械研磨处理（SMAT），然后进行两步时效处理，以促进合金中的沉淀。体相和SMAT层的析出行为不同。时效后，大块显示出含有沉淀物的微晶基体，而表面层的微观结构由具有纳米孪晶的纳米晶粒组成。在SMAT层中没有观察到沉淀物的迹象。时效后表层纳米颗粒的形成归因于再结晶和受控的晶粒生长。由于所选择的加工路线而产生的差异显微组织导致了表面层硬度的增加和材料磨损寿命的增加。
Inconel 718 is a precipitation-strengthened Ni-based superalloy which finds applications across a wide temperature range (up to 650 degrees C). It shows excellent yield strength, ductility, creep resistance and fatigue strength. Surface treatment is known to improve the fatigue life of materials via nano-crystallization of the surface layer. However, the precipitation behavior of the surface-treated layer is largely unexplored. In this regard, the present study aims to investigate and compare the precipitation in the surface-treated layer and the bulk solution-treated IN718. The material is subjected to surface mechanical attrition treatment (SMAT) after solution treatment and is followed by a two-step aging treatment which promotes the precipitation of / in the alloy. The precipitation behavior shown by the bulk and SMAT layer was different. After aging, the bulk shows a microcrystalline matrix containing precipitates, whereas the microstructure of the surface layer consists of nanograins with nanotwins. No evidence of / precipitates were observed in the SMAT layer. The formation of nanograins in the surface layer after aging is attributed to recrystallization with controlled grain growth. The differential microstructures due to the chosen processing route have resulted in increased hardness of the surface layer and increased wear life of the material.