Electromagnetic-shielding effectiveness and fracture behavior of laminated (Ni–NiAl3) composites

Abstract

In this research Ni-NiAl3 multilayer composites were produced through reactive sintering in an open atmosphere using Ni and Al foils with a 250-μm initial thickness. The sintering was performed at 700°C under 2 MPa of pressure for 6 h. The microstructure and phase characterizations of the samples were performed. The hardness values of samples were determined using the Vickers indentation technique for the intermetallic and metallic regions as 765±60 HV and 90±10 HV, respectively. For the mechanical examinations, a perpendicular load was applied to the composite in order to observe the fracture behavior of the metallic-intermetallic laminate composites. SEM fracture surface analyses indicated that cracks initiated in the intermetallic region, and the crack propagation stopped when it reaches the ductile nickel phase. In addition, shielding-effectiveness measurements were performed. The MIL composite exhibits over 50 dB electromagnetic-shielding effectiveness against a very wide frequency range, from a few GHz to over 18 GHz. Keywords: intermetallics, MIL composites, fracture behavior, electromagnetic interference shielding V raziskavi so bili izdelani Ni-NiAl3 ve~plastni kompoziti z reakcijskim sintranjem na atmosferi in z uporabo Ni-in Al-folij z za~etno debelino 250 μm. Sintranje je bilo 6 h na 700°C, pri tlaku 2 MPa. Na vzorcih je bila izvedena karakterizacija mikrostrukture in faz. Trdota vzorcev je bila dolo~ena po Vickersu, 765±60 HV, za podro~ja intermetalnih faz in 90±10 HV pri osnovi. Za mehanske preiskave je bila uporabljena navpi~na obremenitev, za opazovanje obna{anja kompozita pri lomljenju kovinskih in intermetalnih lamel. SEM-preiskave prelomov so pokazale, da je za~etek razpoke v podro~ju intermetalne faze in da se {irjenje razpoke ustavi, ko pride v duktilno fazo niklja. Izvedene so bile tudi meritve u~inkovitosti za{~ite sevanja. MIL kompozit ka`e u~inkovitost pred elektromagnetnim sevanjem, vi{jo od 50 dB v zelo {irokem obmo~ju frekvenc od nekaj GHz do preko 18 GHz. Klju~ne besede: intermetalne zlitine, MIL kompoziti, obna{anje pri lomu, elektromagnetna interferen~na za{~ita

Production and Characterization of Niobium Toughened Ti-TiAl3 Metallic-Intermetallic Composite

“…However, the biggest problem with these materials is the lack of ductility at conventional production temperatures [8]. Low room temperature ductility limits the use of intermetallics and leads to their production by costly production methods [6,[8][9][10][11].…”

Material Analysis and Application for Radio Frequency Electromagnetic Wave Shielding

“…There are numerous studies in the literature on electromagnetic shielding effectiveness and some of them related to our motivation can be found in [1][2][3][4][5][6][7][8][9][10][11][12][13].…”