Question

Q1. For the given materials: silver (Ag); brass (CuZn alloy), tungsten carbide (WC) and alumina (A1203). (10 points) a) Identify the type of bonding between elements in them and name the type of material. b) Comment briefly, on what kind of mechanical, electrical, thermal and optical properties they may possess. c) Comment on what types of defects can be found in each of these materials.

Answer 1

Q. For the given material o) Silver (Ag). b) Ences cuan). c tungsten carbide cwe). d) Alumina C Algoa). Identify the type of bending between them Silver : AG siker is a melal so it con (As) For metallic bond. Generalny silver easily Form melallic bond. elements in eleme cosily con electrons to move & ecally form Compound & Alloyst Brass - It is an alloy which is made of copper (cu zn) zinc. As these two are meval. They can easily form metallic bond. Tungsten Carbide : IL Forms a metallic bond ( wes Generally used for Girnding books & surface material. Generally used in Filements of candesont amb Alumina C Alz C3) 1 is materiaimede between Aluminium & oxygen atoms. It has a chemical bond Generally ionic bond. At low temperature - lonic bond AL high temperatures conclent bond Type of material comes Mela from silver or sold byproducts refining. Brass Alloy, can be vered in proportion to properties Tungsben Carbide - Metal matria Composite Alumina ceramic material i Al2O3 -2A1 & 307 properties: Silver Mechanical properties is in Ing. electrical properties - Grood electrical conducwivity Thermal & optical properties in Ing. 2.

Bress Img 3 Mechanical & Thorman. properties an in some image Electrical properes Good condurkor thermal conductivity of copper. in in have high 237 uur. c) Tungsten Carbide real properties Thermos properties in a Img 4.. has good themet conducivity - 100 woon high a high beiling point booo meiling point 2820 Optical properties in Ing S. a) Alumina. Mech properties in Thermal properties in Img b. high heat resistance & high thermal conducing * high electrical insulation & ngh conrosion Resistance optical properties - Strong & Abrasive wears Dimensional stability. Types OF Defecus a) Silver Agci & Aggr intrinsic cs Schotky, & Boundan point Defect Funnel vacancy si Brass clustering & cracks, cavities. c) Tungscer Carbide Insufficient poor control carbon OF lever. sintered condition d) Alumina : point Defects in Alumina makina.

SILVER:

mechanical properties:

*tensile strength=140Mpa

*poission ratio:0.37

*modulus of elasticity=76 Gpa

*shear modulus=27.8 Gpa

thermal and optical properties:

*thermal expansion=18.9$\mu m/mk$

*thermal conductivity=429W/mk

*thermal diffusivity=174mm²/s

optical properties:

*absorb and scatter light with extra ordinary efficiency.

*I has surface plasom resonance.

*scattering can be controlled by

*size

*shape

*local refractive index

Brass:

Mechanical properties:

*tensile strength=124-310Mpa

*poission ratio=0.31

*shear modulus=37Gpa

thermal properties:

*melting point=885-900 C

*soildus=885C

*liquidus=900 C

Tungsten carbide:

mechanical properties:

*bulk modulus=350

*elastic limit=335

*endurance limit=285

*tensile strength=370Mpa

*youngs modulus=600Mpa

thermal properties:

*high melting point=2870 C

*high boiling point=6000 C

*thermal condutivity =110 W m^_1k^-1

*coeffecient of thermal expansion=5.5$\mu m/mk$

optical properties:

effective means of controlling phase composition in production and rapidily determining some physical parameters such as *width of forbidden band ,electrical conductivity ,dielectric permiablity .

Alumina:

mechanical properties:

*shear modulus=88

*tensile strenth=69

*young's modulus =215

thermal properties:

*thermal condutivity=12

*thermal expansion=4.5

*high heat resistant

*high thermal conductivity

*high electrical insulation

*high corrosion resistant

optical properties of alumina:

*great hardness

*resistance to abrasive wear and dimensional stability

Sorry,I can't upload the properties of material as images.

Thank you.