D-gun Sprayed Fe-Al Single Particle Solidification

Abstract

Some Fe-Al particles less than 50 µm in diameter were deposited onto the steel substrate by means of the D-gun spraying. A solidification mechanism of an individual particle is described. The particle subjected to the description contained nominally 63 at.% Al. The description was preceded by the TEM / SAED analysis of both the Fe-Al coating and Ni-20Cr interlayer. The whole number of the analyzed particles was partially melted during the deposition. The solidification products like: amorphous phase sub-layer, oscillatory sub-layer which contains two types lamellae distributed alternately and typically non-equilibrium phase sub-layer were revealed. In the micro scale, solidification was considered as a process which occurred in two directions: towards the substrate and towards the non-melted particle part. Both solidification processes underwent the positive thermal gradients. The boron addition was localized within the eutectic precipitates pushed and then rejected by the solid/liquid interface of the solidifying non-equilibrium phase. The proposed model is a general one and therefore can be applied to other systems description.Keywords: Fe-Al coating, Ni-20Cr interlayer, rapid solidification, D-gun spraying, boron localization, competitive growth of phases Cząstki proszku Fe-Al mniejsze niż 50 µm w średnicy zostały osadzone detonacyjnie na podłożu stalowym. Opisuje się mechanizm krystalizacji pojedynczej cząstki. Cząstki poddane opisowi zawierały nominalnie 63 at.% Al. Opis poprzedzono badaniami struktury metodą TEM / SAED dotyczącymi zarówno powłoki Fe-Al jak i międzywarstwy Ni-20Cr. Wszystkie analizowane cząstki były częściowo nadtopione podczas osadzania. Zidentyfikowano produkty krystalizacji takie jak: podwarstwę amorficzną, podwarstwę oscylacyjną zawierającą periodycznie ułożone płytki dwu faz oraz podwarstwę zawierającą fazę typowo nierównowagową. W mikroskali proces wzrostu faz jest analizowany jako zachodzący w dwu kierunkach: w stronę podłoża i w stronę niestopionej części cząstki. Obydwa procesy wzrostu zachodziły w obecności dodatniego gradientu temperatury. Bor dodany do powłoki został zlokalizowany w eutektyce odepchniętej przez front krystalizacji fazy typowo nierównowagowej. Proponowany model ma charakter ogólny i może być zastosowany do opisu innych systemów.

The Effect of Nanometric α-Al2O3 Addition on Structure and Mechanical Properties of Feal Alloys Fabricated by Lens Technique

“…[5,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]37]. However, these methods are complex, inefficient, energy-consuming and generates high production costs.…”

“…In recent years intermetallic based alloys from transition metals -aluminum binary systems (e.g. Ni-Al [12][13][14][15][16][17][18] or Fe-Al [19][20][21][22][23][24][25]), so called aluminides, have gathered a lot of attention from both scientific and industrial environments in terms of their high temperature applications. Fe-Al intermetallic alloys exhibit a high resistance towards oxidation, carbonization and corrosion at elevated temperature, that make them competitive to conventional high temperature materials.…”

Inverse Model for the Solute Micro-Field Formation during Self-Propagating High Temperature Reaction

“…: Al 3 Ni 2 , and Al 3 Ni. The appearance of the mentioned phases is justified thermodynamically and additionally by the Phase Rule applied for the isothermal / isobaric formation of this complex, [2]. These intermetallic phases form a kind of a diffusion barrier and complicate the SHS -reaction.…”

Wire Electrical Discharge Machining Of Feal Intermetallic Sinters Without And With Addition Of Nano-Al2O3 Oxide Ceramic

“…These materials can be produced by a conventional melting and casting, but finally obtained coarse-grained structure required further multivariant thermo-mechanical treatment [11][12][13][14]. Nowadays, Fe-Al intermetallics are usually used as a protective coatings deposited by a detonation gas spraying [15][16][17][18][19][20][21][22][23][24] and a laser cladding [25][26][27][28]) or as reactive, exothermic mixtures (consisted of Fe and Al elemental powder) for joining other materials (e.g. in the form of thin foils) [29].…”