High coercivity in Sm–Fe–Ti alloys by rapid solidification

PtCo hard magnets have specialized applications owing to their relatively high coercivity combined with corrosion resistance and ductility. Increased intrinsic coercivity has been recently obtained by rapid solidification processing of PtCo alloys containing boron. After rapid solidification by double anvil splat quenching and subsequent annealing for 30 minutes at 650°C, an alloy with composition Pt42Co45B13 (at.%) exhibited intrinsic coercivity up to 14kOe. This represents a significant improvement compared to the average coercivities in conventional binary PtCo alloys of 5 to 8 kOe.Rapidly solidified specimens of Pt42Co45B13 (at.%) were annealed at 650°C and 800°C for 30 minutes. The magnetic behavior was characterized by measuring the coercive force (Hc). Samples for TEM analysis were mechanically thinned to 100 μm, dimpled to about 30 nm, and ion milled to electron transparency in a Gatan Duomill at 5 kV and 1 mA gun current. The incident ion beam angle was set at 15° and the samples were liquid nitrogen cooled during milling. These samples were analyzed with a Philips CM20T TEM/STEM operated at 200 kV.

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THE PRODUCTION OF ULTRAFINE DISPERSIONS OF RARE EARTH OXIDES IN Ti ALLOYS USING RAPID SOLIDIFICATION

Rapidly Quenched Metals ◽

10.1016/b978-0-444-86939-5.50227-x ◽

1985 ◽

pp. 953-956 ◽

Cited By ~ 3

Author(s):

O.G. KONITZER ◽

B.C. MUDDLE ◽

R. KIRCHHEIM ◽

H.L. FRASER

Keyword(s):

Rare Earth ◽

Rapid Solidification ◽

Rare Earth Oxides ◽

Ti Alloys

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Strengthening of Cu–Ti Alloys by Rapid Solidification Processing

Powder Metallurgy ◽

10.1179/pom.1991.34.3.199 ◽

1991 ◽

Vol 34 (3) ◽

pp. 199-204 ◽

Cited By ~ 8

Author(s):

D. Božić ◽

M. Mitkov

Keyword(s):

Rapid Solidification ◽

Rapid Solidification Processing ◽

Solidification Processing ◽

Ti Alloys

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Interplay between eutectic and dendritic growths dominated by Si content for Nb-Si-Ti alloys via rapid solidification

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4052760 ◽

2021 ◽

pp. 1-20

Author(s):

Yueling Guo ◽

Lina Jia ◽

Junyang He ◽

Siyuan Zhang ◽

Zhiming Li ◽

...

Keyword(s):

Electron Beam ◽

Rapid Solidification ◽

Atom Probe ◽

Ti Alloys ◽

Transmission Electron ◽

Scanning Transmission ◽

Beam Surface ◽

Si Content ◽

Design And Manufacture ◽

Fully Lamellar

Abstract Rapid solidification techniques such as electron beam additive manufacturing are considered as promising pathways for manufacturing Nb-Si based alloys for ultra-high-temperature applications. Here we investigate the microstructure diversity of a series of Nb-Si-Ti alloys via electron beam surface melting (EBSM) to reveal their rapid solidification behaviors. Results show that the microstructural transition from coupled to divorced Nbss/Nb3Si eutectics can be triggered by increasing Si content. The formation of fully lamellar eutectics, evidenced by scanning transmission electron microscopy and atom probe tomography (APT), is achieved in the EBSM-processed Nb18Si20Ti alloy (at%), in contrast to the hypereutectic microstructures in arc-melted counterparts. The dendritic microstructures containing divorced eutectics are generated with a higher content of Si during rapid solidification. The transition from faceted to non-faceted growth of intermetallic Nb3Si occurs with the formation of primary Nb3Si dendrites. The interplay between eutectic and dendritic growths of silicides is discussed to provide insights for future alloy design and manufacture.

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