FRACTURE TOUGHNESS CHARACTERISTICS OF 6063 (H9) ALUMINIUM ALLOY

Abstract

6063 (H9)alumin3iim alloy has been used for making struc-tures for Second Indian Expediti.an to Antarctica. Fracture toughness characteristics of this alloy are not known at ambient and subzero temperatures. So an effort has been made to conduct these studies, using fatigue pre-cracked chirpy specimens and liquid nitrogen. Universal Fatigue Testing Machine was used to produce fatigue pre- crocks i.n the specimens. Temperatures down to -120°C have been obtained using liquid nitrogen. Pre-cracked specimens at different temperatures were tested in Chexpy,;mpact Testing Machine. Result of this investigation show that this alloy, is not very much prone to ductile brittle transition, and the dynamic .fracture toughness, Kid, decreases with the decrease In temperature upto -50°C and then remains almost constant,