Effect of titanium nitride nanoparticles on grain size stabilization and consolidation of cryomilled titanium

Nanocrystalline Al-Mg with extreme strength due to grain boundary doping

“…It is common to find kinetic mechanisms in the literature and commercially that metallic systems often contain second-phase particles that act as barriers to driving forces enabling grain boundary migration and grain growth. Second-phase particles 3 and drag elements inhibit grain growth through a process known as Zener pinning, where fine particulates reside in the grain boundaries and prevent migration by exerting pressure opposite to the driving forces [13]. Both images taken using bright field transmission electron microscopy (BF TEM) in Fig 1.1 show second-phase particles pinning grain boundaries and restricting grain boundary movement [13,14].…”

“…Second-phase particles 3 and drag elements inhibit grain growth through a process known as Zener pinning, where fine particulates reside in the grain boundaries and prevent migration by exerting pressure opposite to the driving forces [13]. Both images taken using bright field transmission electron microscopy (BF TEM) in Fig 1.1 show second-phase particles pinning grain boundaries and restricting grain boundary movement [13,14]. Zener pinning therefore increases the activation energy for grain growth and allows a material to preserve fine grain size.…”

“…Zener pinning therefore increases the activation energy for grain growth and allows a material to preserve fine grain size. [13] and (b) four types of inert particles in a Ni-based alloy where they reside in and pin grain boundaries [14].…”

Cryogenic Milling of Titanium Powder

“…Milling under cryogenic temperatures (typically in liquid nitrogen (LN) or liquid argon (LAr) slurry) can be employed to suppress recovery and dynamic recrystallization. Cryogenic milling leads to the reduction of powder crystallite size to the order of tens of nanometers for aluminium [7] and for titanium and its alloys [15,17,18]. At the same time, the diffusivity of possible contaminating elements such as N or O is significantly reduced [17].…”

Characterization of Commercially Pure Ti Powders Prepared by Cryogenic Milling

“…To suppress recovery and dynamic recrystallization during milling, cooling to cryogenic temperatures (typically by liquid nitrogen (LN) or liquid argon (LAr)) can be employed leading to the reduction of powder crystallite size (measured by X-ray diffraction) to the order of tens of nanometers (e.g. for aluminium [8] and titanium and its alloys [5,9,10]). * corresponding author; e-mail: Jiri.Kozlik@seznam.cz…”