Flashcards
lecture 1
Flashcards do conjunto (21)
- 1Materials ScienceMaterial science is the investigation of the relationship among processing, structure, properties, and performance of materials.
- 2Materials EngineeringThe discipline of designing or engineering the structure of a material to produce a predetermined set of properties based on established structure-property correlation.
- 3The major types of materials- Metals
- Ceramics
- Polymers
- Composites
- Advanced materials - 4MetalsSteel, Cast Iron, Aluminum, Copper, Titanium, etc.
- 5CeramicsGlass, Brick, Alumina, Zirconia, SiN, SiC
- 6PolymersPlastics, Nylon, “glue”
- Polymers include plastics and rubber materials
- Polymers are typically inexpensive and
are characterized by ease of formation
and adequate structural properties. - 7CompositesGlass Fiber-reinforced polymers, Carbon Fiber reinforced polymers, Metal Matrix Composites, etc.
- 8Advanced materialsSemiconductors, Biomaterials, Smart materials
- 9Materials Properties, Structure and Processing- The properties of a material depend upon its composition and micro structure.
- The micro structure of a material depends upon its composition and the processing that it undergoes.
- Structure determines Properties but Processing determines Structure! - 10Properties of materials- Mechanical
- Electrical
- Thermal
- Magnetic
- Optical - 11Electrical Resistivity of CopperElectrical Resistivity of
Copper is affected by:
• Contaminate level
• Degree of deformation
• Operating temperature
- Adding “impurity” atoms to Cu increases resistivity.
- Deforming Cu increases resistivity. - 12ThermalThermal Conductivity of Copper:
--It decreases when you add zinc! - 13MagneticMagnetic Permeability vs. Composition:
--Adding 3 % atomic Si makes Fe a better recording medium. - 14OpticalTransmittance:
- Aluminum oxide may be transparent, translucent, or opaque depending on the “grain structure.
- Grain Structure is a function of “Solidification” processing! - 15Materials Selection Process1. Pick Application Determine required Properties
2. Properties Identify candidate Material(s) Material: structure, composition.
3. Material Identify required Processing
Processing: changes structure and overall shape ex: casting, sintering, vapor deposition, forming, joining, annealing. - 16Inputs to the Design Process• Customer needs
• Aesthetics
• Function
• Value
• Design concepts
• Environmental
dynamics
• Scientific advances - 17Consequence of not understanding• Component failure
• Inappropriate performance (bends instead of being rigid)
• Inappropriate properties (conductor instead of insulator) - 18Materials Mechanical Properties- Elastic Modulus ‘E’ (a measure of the stiffness of a material)
(also known as Young’s Modulus or Modulus of Elasticity), GPa
- Yield Strength, ‘σy’ (maximum stress before plastically deforms), MPa
- Tensile Strength, ‘σts’ (maximum tension without tearing), MPa
- Hardness (resistance to indentation) - 19Tensile stress-strain curves for ceramics•Entire response is elastic
•Yield strength not
reached before failure
•Young’s modulus is the
slope of this region - 20Tensile - stress strain curves for polymers - Ductile Response• At the yield point, strain
without load increase due
to sudden increase in
number of dislocations of
the material’s atomic
structure.
•Permanent deformation occurs at stresses beyond the yield strength
– material will not return to its original shape past this point. - 21Stress and strain- A flexible material – has a low ‘young’s modulus ‘E’’
- Large ‘yield strength’ δy – hard to deform
- High tensile strength – more stress (load) a material can withstand before breaking.
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- Bachelors Materials & manufacturing FlashCards sobre lecture 1, criado por Natalia Rehakova em 11-05-2016.
- Criado por
- Natalia Rehakova
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