Abstract

This paper reports investigation on the effect of heat-treatment on the microstructure, mechanical, tribological and corrosion characteristics of laser directed energy deposition (LDED) built stainless steel (SS 316) bulk structures. LDED built SS 316 structures are subjected to solution treatment at 1073 K (HT1073) and 1273 K (HT1273) and reduction in ferrite phase with heat-treatment is observed from microstructure. X-ray diffraction and microstructure shows that the austenite phase is observed at all conditions and reducing ferrite phase intensity is noticed with an increase in heat-treatment temperature. Improvement in the plasticity retaining capacity and reduction in micro-hardness by 72.8% and 6.75% are noticed with heat-treatment, respectively. It is observed that the corrosion rate and specific wear rate increases after heat-treatment. The maximum specific wear rate of 0.19375 × 10^–4 mm³/min is observed in the HT1273 sample with wide and deep grooves noticed on the worn out surface of heat-treated samples. The SEM images of wear track is characterized with abrasive wear mechanism for as-built sample, while heat-treated samples shows plastic deformation, followed by spalling effect. The work paves a way to understand the effect of heat-treatment on LDED built SS 316 bulk structures.

Graphic Abstract

中文翻译：

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热处理对基于激光定向能量沉积增材制造的SS 316结构的组织，力学性能和腐蚀行为的影响

摘要

本文报告了热处理对激光定向能量沉积（LDED）内置不锈钢（SS 316）整体结构的微观结构，机械，摩擦学和腐蚀特性的影响的研究。LDED制成的SS 316结构在1073 K（HT1073）和1273 K（HT1273）进行固溶处理，并从微观结构观察到热处理导致铁素体相减少。X射线衍射和显微组织表明，在所有条件下均观察到奥氏体相，并且随着热处理温度的升高，铁素体相强度降低。通过热处理分别观察到可塑性保持能力的提高和显微硬度的降低分别为72.8％和6.75％。观察到，热处理后腐蚀速率和比磨损速率增加。在HT1273样品中观察到^–4 mm ³ / min，在热处理样品的磨损表面上发现宽而深的凹槽。磨损轨迹的SEM图像具有磨损样品磨损机理的特征，而热处理后的样品表现出塑性变形，随后出现剥落效应。这项工作为了解热处理对LDED建造的SS 316整体结构的影响铺平了道路。

图形摘要