Parameter TA BL E 11.1 Some material properties used to match materials with functional,environmental, Summary4,5 manufacturing,and economic requirements. Property Interpretation Common or Related Measure Mechanical Properties Strength Ability to resist breaking Yield stress Stiffness Ability to resist bending Modulus of elasticity Ductility Permanent deformation before breaking elongation Toughness Ability to withstand impact or Energy or work necessary to resist breaking fracture material Hardness Ability to resist abrasion/scratching Scores on hardness tests Creep Gradual,continuing deformation under Creep strength an applied constant stress Electrical Properties Resistance Opposition to passage of electrical current Electrical Resistivity R Conductance Ability to conduct electrical current Electrical Conductivity C=1/R Dielectric strength Highest voltage that can be applied to DS =Breakdown voltage/ insulator without electrical breakdown insulator thickness Thermal Properties Thermal Ability to conduct heat Amount of heat per second conductivity flowing through a temperature gradient△T Specific heat Heat per unit mass needed to raise Amount of heat/(mass x AT) capacity temperature T by an amount AT continuedME 350 13 Parameter Summary 4,5