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Usage of the optical microscope to observe steel microstructure, i.e. " Der Vorgang kann demnach so gedacht werden, dass das Zink seine krystallinische Struktur, die es beim Erstarren annimmt, durch das Walzen verliert und wenn es auf eine Temperatur erwaermt wird, welche diejenige, die es beim Walzen erhaelt, überschreitet, die krystallinische Struktur wiedergewinnt." It was then that the misleading term "recrystallization" has been given birth: Kalisher 1, in 1881, in Germany, working with zinc strips, suggested that plastic deformation "destroyed the crystallinity" of the zinc, however subsequent annealing caused its restoration. " Every work of gold and silver as well as copper may be worked either hot or cold, only you must be careful to anneal the thing at every hammering or when it needs it" The knowledge available of these phenomena, at the time of the great discoveries, are well summarized in Biringuccio's quote in 1540 in the classical book De La Pirotechnia: Therefore, some knowledge concerning strain hardening, softening by annealing and by hot working was already available at that time. For instance, people that lived five thousand years ago in the regions next to the Persian Gulf, Irak nowadays, have mechanically worked copper, gold, and silver. The plastic working of metallic materials has been practiced for millennia. The knowledge of the phenomena such as work hardening, recovery, recrystallization, and grain growth is of fundamental importance not only to correctly work these materials but also to control their microstructures and optimizing their properties. Forging, rolling, extrusion and drawing deform about 90% of the production of metals and alloys. It is estimated that there are more than 40.000 metallic alloys.

The production of metallic materials is impressive not only due to the quantity produced, more than 10 9 tons/year, but also due to its diversity. Keywords: recrystallization, recrystallisation, recovery, nucleation, growth Finally, the growth step is highlighted, emphasizing boundary and sub-boundary mobilities and the forces acting on the high angle grain boundaries that sweep the microstructure during recrystallization. The recrystallization nucleation mechanisms are subsequently discussed. Definitions and concepts involving recrystallization are presented regarding it as a solid-state reaction that occurs by nucleation and growth. Initially the main developments concerning recrystallization are presented from a historical perspective. The evolution in the understanding of the recrystallization phenomena is summarized in this paper. IVEscola Politécnica, USP, 05508-900 São Paulo - SP, Brazil

IIIDEMAR, FAENQUIL, 12600-970 Lorena - SP, Brazil IEEIMVR, UFF, 27255-125 Volta Redonda - RJ, Brazil Paulo Rangel Rios I Fulvio Siciliano Jr II Hugo Ricardo Zschommler SandimIII, * Ronald Lesley Plaut IV Angelo Fernando Padilha IV 10.Nucleation and growth during recrystallization Three days of mourning were announced in the city and some have suggested the entire country should forego the traditional New Year celebrations, Russia’s major winter holiday equivalent to Christmas and Thanksgiving, when families gather to eat and drink together in a celebration that runs through Jan. The attacks in Volgograd - a ciity venerated throughout Russia as the wartime city of Stalingrad that witnessed the historic battle that was the turning point in the Red Army’s struggle against the invading Nazi armies - have left Russia reeling. Earlier this year, he warned that in the run up to the Winter Olympics, Russian citizens would not be safe from terrorist attacks. STORY: Weekend Bombings Raise Safety Concerns for Sochi OlympicsĪlthough no group has claimed responsibility for the Volgograd bombings, Islamist leader Doku Umarov is believed to be behind them. Sochi is roughly 400 miles from Volgograd. The bombings at Volgograd’s main railway station on Sunday and in a bus packed with students going to their last college classes on Monday have renewed concerns about security at the Winter Olympics in Sochi, which militants have vowed to target. “In the past year we have faced problems and serious challenges, including the inhuman terror attacks and unprecedented disasters in the Far East,” he said. In the somber televised address to a nation facing its grimmest New Year’s celebrations in many years, Putin also reminded Russians that the nation is resilient. His comments were broadcast as the first funerals took place for the victims of the bombings, which also wounded 100 people.