STUDI EQUAL CHANNEL ANGULAR PRESSING (ECAP) SUHU NITROGEN CAIR PADA PADUAN Al-Mg-Si (Al 6061) [A Study On Equal Channel Angular Pressing At Liquid Nitrogen Temperature Of Al – Mg – Si (Al 6061) Alloys] - Efendi Mabruri; I Nyoman Gede; Edy Priyanto Utomo (National Research and Innovation Agency (BRIN), 2014)