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Affiliation of Author(s):Shandong University, Weihai

Journal:Materials Chemistry and Physics

Key Words:Passive film; Corrosion resistance; Selective laser melting; Heat treatment; Heat treatment

Abstract:Studying the corrosion behavior of nickel-based high-temperature alloy parts manufactured by selective laser melting (SLM) technology is a necessary research field for expanding their application scope and conducting targeted electrochemical secondary machining. Previous researches focused on the corrosion characteristics of alloy matrix, but the corrosion resistance is also closely related to the passive film-forming performance. Consequently, this article employed heat-treated Hastelloy X as a case study and utilized electrochemical testing methods to assess alterations in passive film-forming performance. Then Laser confocal microscopy (LSCM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were employed to observe the polarized surface, the microstructure and element segregation, and to analyze the factors affecting the passive film-forming performance. The results showed that after heat treatment at 1000 °C, the precipitation quantity and grain size decreased because of recrystallization, enhancing the passive film-forming performance. During potentiostatic polarization, the current density can remain stable for a long time, and a relatively dense passivation film residue can be observed on the surface after potentiodynamic polarization. The 800 °C heat-treated specimens have preferential corrosion zones (along the original scanning trajectory edge), where the insoluble precipitates are more concentrated, resulting in the rupture of the passive film and the pitting corrosion. The film-forming performance of 1175 °C heat-treated specimens is also degraded, attributed to the growth of grains and the precipitation of Cr element (an increase of 5 % compared to other specimens from about 20 % to 25 %).

All the Authors:Wenchao Guan, Kan Wang

First Author:Yipeng Qin

Indexed by:Research Paper

Correspondence Author:Yong Liu

Document Code:10.1016/j.matchemphys.2025.130453

Document Type:Journal article

Volume:334

Page Number:130453

ISSN No.:0254-0584

Translation or Not:no

Date of Publication:4574-08-01