Amorphization and Nano-Crystallization of Ni-Nb Coating on GH3039 Alloys by High Current Pulsed Electron Beam.

Conglin Zhang,Peng Lyu,Jie Cai,Jiahong Wang,Zirun Yang,Qingfeng Guan,Xuesu Ji,Lingfan Lu

doi:10.3390/nano11020347

Abstract

In this paper, the Ni-Nb coatings were successfully prepared onto the GH3039 alloys by High current pulsed electron beam (HCPEB). The transmission electron microscopy (TEM) results confirmed that the Ni-Nb layer of 10-pulsed samples exhibited partial amorphization, which was consisted of γ-Ni particles, rod-like Ni3Nb particles and nano Ni3Nb with 30 nm in size. After 20-pulsed irradiation, the results show that only Ni3Nb clusters with around 3 nm in size were dispersed in fully amorphization layer. With increased pulse number to 30, the nano-particles embedded into the amorphous layer were grown up, the size of which was about 8 nm. The microstructure evolution during HCPEB irradiation was from the partial amorphous to fully amorphous and then to nano-crystallization. The 20-pulsed samples possessed the best hardness and corrosion resistance. The ultrafine clusters uniformly embedded into amorphous layer were main reason for improving properties.

Highlights

Amorphous structures have been prepared in the binary Nb component ratio (Ni)-X systems, while NiNb system is one of the best binary metallic glass forming systems due to their unique properties including excellent properties, high corrosion resistance and various magnetic properties [1,2,3]
The GH3039 superalloy was composed of C ≤ 0.08%, Mn = 0.40%, Mo = 1.80%, P = 0.02%, Al/Ti = 0.75%, Fe = 3.00%, Si = 0.80%, S = 0.012%, Cr = 22.00%, Nb = 1.30%, and Ni = balance
As-fabricated single Ni-Nb coating was obtained onto the topmost of GH3039 alloy

Summary

Introduction

Amorphous structures have been prepared in the binary Ni-X systems, while NiNb system is one of the best binary metallic glass forming systems due to their unique properties including excellent properties, high corrosion resistance and various magnetic properties [1,2,3]. Ni-Nb alloys exhibited a wide composition range (40–60%) to form amorphous structures. The best forming composition of the amorphous phase was Ni = 32% and. Amorphous alloys possessed very low ductility as per-experiment study according to the reference [8]. It is hard for researchers to fabricate amorphous alloys to ensure its thermal stability that is another drawback. The free energy would be reduced through crystallization for the amorphous alloys. Several properties of amorphous alloys with the nanoscale crystal structure were found to be fundamentally different from, and often superior to, those of the conventional polycrystals and amorphous solids. Nano-crystalline may enhance the strength, and ductility of materials and so on [9,10], which could remedy the above drawbacks

Objectives

Methods

Results