Production of bulk amorphous alloys: application an metallic alloys an magnetocaloric intermetallic compounds

Author(s)

Rockfeller Maciel Peçanha

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica
• Defense date: 2006-02-15

Examining board members

Rubens Caram Junior; Maria Clara Filippini Ierardi; Rodnei Bertazzoli; Adelino de Aguiar Coelho

• Advisor: Sergio Gama; Rubens Caram Junior

Abstract

The aim of this work was to obtain metallic and magnetocaloric bulk amorphous alloys through centrifugation and injection processes. In order to obtain metallic bulk amorphous alloys a vacuum injection apparatus was built. For testing the centrifugation and injection equipments, known metallic bulk amorphous alloys were used. The alloy classified as structural amorphous steel, Fe43,6355Cr4,925Co4,925Mo12,608Mn11,032C15,563B5,8115Y1,5, was obtained in bulk amorphous by centrifugation with a thickness of at least 1 mm. The Zr52,5Ti5Al10Cu17,9Ni14,6 and Cu55Zr30Ti10Ni5 alloys were obtained in bulk amorphous by injection. For obtaining amorphous alloys it was used three relevant rules: confusion principle, deep eutectics, and high viscosity. The Gd55Ga20Si20Ge3B2 alloy was obtained amorphous in bulk by centrifugation and showed the largest table-like magnetocaloric effect, ?T = 142 K for a magnetic field variation of 1 T, and it is the unique based-Gd magnetocaloric bulk amorphous alloy. The Gd50Al23Mn23B2Ga2 and Fe43,6355Cr4,925Co4,925Ni12,608Mn11,032C15,563B5,8115Y3,0 alloys were developed in this work and only obtained as amorphous alloys, not in bulk, using the splat-cooler equipment. The results obtained are important and show new ways for obtaining new magnetocalric materials for magnetic refrigerators and vacuum injection apparatus (AU)