Synthesis of Fe-Al-Ti Based Intermetallics with the Use of Laser Engineered Net Shaping (LENS)

Materials

Monika Kwiatkowska²  Dariusz Zasada²  Jerzy Bystrzycki²  Marek Polański¹ 

[1]Department of Advanced Materials and Technologies, Military University of Technology, 2 Kaliskiego Str., 00-908 Warsaw, Poland

关键词: iron aluminides;    LENS;    laser cladding;    rapid solidification alloying;    microstructure;    synthesis;   

DOI  :  10.3390/ma8052311

来源: mdpi

【 摘 要 】

The Laser Engineered Net Shaping (LENS) technique was combined with direct synthesis to fabricate L2₁-ordered Fe-Al-Ti based intermetallic alloys. It was found that ternary Fe-Al-Ti alloys can be synthesized using the LENS technique from a feedstock composed of a pre-alloyed Fe-Al powder and elemental Ti powder. The obtained average compositions of the ternary alloys after the laser deposition and subsequent annealing were quite close to the nominal compositions, but the distributions of the elements in the annealed samples recorded over a large area were inhomogeneous. No traces of pure Ti were observed in the deposited alloys. Macroscopic cracking and porosity were observed in all investigated alloys. The amount of porosity in the samples was less than 1.2 vol. %. It seems that the porosity originates from the porous pre-alloyed Fe-Al powders. Single-phase (L2₁), two-phase (L2₁-C14) and multiphase (L2₁-A2-C14) Fe-Al-Ti intermetallic alloys were obtained from the direct laser synthesis and annealing process. The most prominent feature of the ternary Fe-Al-Ti intermetallics synthesized by the LENS method is their fine-grained structure. The grain size is in the range of 3–5 μm, indicating grain refinement effect through the highly rapid cooling of the LENS process. The Fe-Al-Ti alloys synthesized by LENS and annealed at 1000°C in the single-phase B2 region were prone to an essential grain growth. In contrast, the alloys annealed at 1000°C in the two-phase L2₁-C14 region exhibited almost constant grain size values after the high-temperature annealing.

【 授权许可】

CC BY   
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