PC of materials t2

• What is conductivity?


  The electrical resivity of a material that quantifies how strongky that material opposes flow of electric current
• What does strength mean?


  Strength of materials which deals with the behaviour of solid objects subject to stresses and strains, tension, compression, shear, torsion
• What is compression?


  Forces pressing together or ability to withstand loads applied from both ends acting inwards
• What is an Ametek test?


  A test for compression
• What is torsion?


  load producing twisting of a body around its longitudinal axis, can withstand if fixed at both ends
• What is tension?


  The ability to withstand stretching forces tensile pulling on both ends of a peice of material
• What test checks for tension?


  Universal testing machine
• What is torsion?


  This is to test the ability of material fixed at both ends to withstand the shear force applied to it
• What is elasticity?


  Elasticity refers to the ability of an object or material to resume its normal shape after being stretched or compressed
• What is plasticity?


  Refers to the ability and quality of a material being easily shaped or moulded, the ability of any material to change shape
• What is malleability?


  Ability to deform under pressure known as compressive stress, material may be flattened into thin sheets eg copper
• What is ductility?


  When a solid material stretches under tensile stress, ductility is a measure of a materials ability undergo significant plastic deformation before rupture
• How is ductility measured?


  Tensile test
• What is hardness?


  Measure of resistance to localised plastic deformation induced by either mechanical indentation or abrasion
• What can measure hardness?


  Rockwell scale, measures the depth of penetration
• What is toughness?


  The ability of a material to absorb energy and plastically deform without fracturing
• What measures toughness?

  IZOD impact testing rig
• What is durability?


  durability is the ability of a material to withstand wear, especially as a result of weathering
• What is biodegradablility?


  the ability of organic substances to be broken down into simpler substances through the action of enzymes through micro organisms eg bio polymer starch
• Name biodegradable materials


  Cotton, wool, wood, human and animal waste