Microstructure Modifications and Associated Corrosion Improvements in GH4169 Superalloy Treated by High Current Pulsed Electron Beam

Yichang Su,Guangyu Li,Liyuan Niu,Shengzhi Yang,Qingfeng Guan,Jie Cai

doi:10.1155/2015/876539

Abstract

The surface of the nickel-based superalloy GH4169 was subjected to high-current pulsed electron beam (HCPEB) treatment. The microstructural morphologies of the material were analysed by means of optical microscope (OP), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results reveal that the irradiated surface was remelted and many craters were formed. The density of craters decreased with the increment of HCPEB pulses. After 20-pulsed HCPEB irradiation, nanostructures were formed in the melted region of the surface. Furthermore, slipping bands and high density of dislocations were also formed due to the severe plastic deformation. The selective purification effect, homogenized composition, nanostructures, and dislocation slips introduced by HCPEB irradiation bring a significant improvement of corrosion resistance of GH4169 superalloy.

Highlights

High-current pulsed electron beam (HCPEB) has proved to be a powerful tool for surface modification of metallic materials [1,2,3,4]
Nickel-based superalloy GH4169 (Inconel 718) was initially developed for the use as a structural material in aircraft gas turbine engines for the aerospace industry, but it is extensively used in the oil and gas industry for a variety of applications due to its excellent mechanical properties, superior high temperature properties, and good corrosion resistance up to 650∘C [7,8,9]
Surface microstructure of the samples was performed by using optical microscope (OP) of type LEICA DM-2500M and scanning electron microscope (SEM) of type JSM-7100F

Summary

Introduction

High-current pulsed electron beam (HCPEB) has proved to be a powerful tool for surface modification of metallic materials [1,2,3,4]. During the process of HCPEB irradiation, a high energy (108-109 W/cm2) is instantly deposited in a thin layer (less than tens of micrometers) within a short time (a few microseconds). Nickel-based superalloy GH4169 (Inconel 718) was initially developed for the use as a structural material in aircraft gas turbine engines for the aerospace industry, but it is extensively used in the oil and gas industry for a variety of applications due to its excellent mechanical properties, superior high temperature properties, and good corrosion resistance up to 650∘C [7,8,9]. The microstructural formation mechanism, especially the surface nanocrystallization, and the associated corrosion properties are investigated.

Experimental

Results and Discussion

Conclusions