# Mat Sci Ch 8

 What are the 2 types of fracture possible for metals? 1) Ductile2) Brittle The two steps involved in fracture process: 1) crack initiation2) crack propagation The crack propagatoin for a __(1)__ fracture is slow and stable while it is sudden and rapid for __(2)__ fracture. 1) Ductile2) Brittle Why is Ductile fracture almost preferred more than Brittle fracture? 1) Brittle fracture occurs suddenly & satastrophically2) Ductile fracture gives warning Brittle fracture can be catagorized into two types: 1) Triangranular (through grains)2) Intergranular (along grain boundaries) A measure of a material's resistance to brittle fracture when a crack is present. Fracture toughness What are the two types of impact testing techniques for fracture toughness? 1) Charpy v-notch (CVN)2) Izod Decreasing the grain size of low strength steels does what two things to the metal? What is the opposite method? 1) decreases the strength2) lowers the DBT temperature, hence toughens it. - Increase Carbon content A form of failure that occurs in structures subjected to fluctuating stress. Fatigue Three types of Cyclic stresses: 1) Axial (tension-compression)2) Flexural (bending)3) Torsional (twisting) Three different fluctuation stress-time modes: 1) Reversed stress cycle2) Repeated stress cycle3) Vary randomly in amplitude and frequency The stress level at which failure will occur for some specific number or cycles. Fatigue strength The number of cycles to cause failure at a specified stress level. Fatigue life The three steps by which failure is characturized by: 1) crack initiation2) crack propagation3) Final failure Failure that occurs by simultaneous action of cyclic stress and chemical attack. Corrosion fatigue Deformation under constant static load (or stress) at elevated temperature are termed as what? Creep AuthorDusyat ID112492 Card SetMat Sci Ch 8 DescriptionMaterial Science Chapter 8 Updated2011-10-27T03:33:44Z Show Answers