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-mu m initial thickness. The sintering was performed at 700 degrees 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.