Microstructural, Magnetic, and Nanoindentation Studies of the Ball-Milled Ti80Ni20 Alloy

Nanostructured Ti 80 Ni 20 material was elaborated by mechanical alloying from pure Ti and Ni powders in a planetary ball-mill P7 under argon atmosphere at ambient temperature. Morphological, microstructural, magnetic, and nanoindentation properties were studied using scanning electron microscopy, X-ray diffraction, magnetic measurements, and nanoindentation test. The morphological observations show the predominance of the welding phenomenon during the milling process. The Rietveld refinement of the X-ray diffraction pattern reveals, after 4 h of milling, the formation of the disordered hcp-Ti (Ni) solid solution in addition to elemental hcp-Ti and fcc-Ni. On further milling (20 h), the interdiffusion between Ti and Ni atoms is evidenced by the formation of disordered hcp-Ti (Ni) and fcc-Ni (Ti) solid solutions. The saturation magnetization and coercivity values are about of 159.8 emu/g and 80.79 Oe, respectively, after 20 h of milling. M r / M s ratio indicates the existence of small magnetic particles which are typically single domains ( M r / M s 0.1–0.5) and/or multidomain ( M r / M s < 0.1). Nanohardness values of the sintered powders fluctuates between 1.53 and 5.98 GPa while those of the elastic modulus varies in the range 130.73 to 164.53 GPa.