Mechanical Behavior of metallic Materials Toughness An important material characteristic which is the resistance to fracture(measured in units of energy For an unnotched tensile bar, the energy to break may be estimated from the area under the stress-strain curve energy/volme=l. od8 Maximum toughness is achieved with a optimum combination of strength and ductility which provides for large fracture energy absorption. ③大季
Mechanical Behavior of Metallic Materials Toughness An important material characteristic which is the resistance to fracture (measured in units of energy). For an unnotched tensile bar, the energy to break may be estimated from the area under the stress-strain curve. 0 / f energy volme d = Maximum toughness is achieved with a optimum combination of strength and ductility which provides for large fracture energy absorption
Mechanical Behavior of Metallic materials A C B ③大季
Mechanical Behavior of Metallic Materials
Mechanical Behavior of metallic Materials Temperature and Strain-rate Effects It is known that the general flow curve for a given material will decrease with increasing temperature T and decreasing strain-rate & T2 T1>72>73 >∈2> (b)
Mechanical Behavior of Metallic Materials Temperature and Strain-rate Effects It is known that the general flow curve for a given material will decrease with increasing temperature T and decreasing strain-rate . &
Mechanical Behavior of metallic Materials There is a relationship between true stress and strain rate. o=K&& Where m=strain-rate sensitivity factor strain rate K=material constant F= true stress ③大季
Mechanical Behavior of Metallic Materials m = K & Where m = strain-rate sensitivity factor = strain rate K = material constant = true stress & There is a relationship between true stress and strain rate
Mechanical Behavior of metallic Materials e For most metals. m is low and varies between 0.02 and 0.2. Under certain conditions, wherein m >0.3, a given material will exhibit a significant degree of strain-rate sensitivity in association with superplastic deformation behavior m=1. the material is analogous to that associated with Newtonian viscous flow CHONGQING UNIVENTTY
Mechanical Behavior of Metallic Materials ⚫ For most metals, m is low and varies between 0.02 and 0.2. ⚫ Under certain conditions, wherein m > 0.3, a given material will exhibit a significant degree of strain-rate sensitivity in association with superplastic deformation behavior. ⚫ m = 1, the material is analogous to that associated with Newtonian viscous flow