Metals and alloys

Question 1

transition states

Answer 1

solid
liquid
gas

Question 2

dental metals

Answer 2

amalgam
gold 
titanium
cobalt chromium
stainless steel

Question 3

metal

Answer 3

crystalline material
held in metallic bonds
cations in laccice with electrons
7 types of lattice

Question 4

types of crystal structure

Answer 4

face centered cubic

body entered cubic

Question 5

packing factors ofFCC and BCC

Answer 5

fcc - 0.74

BCC - 0.6(more space due to lower packing factor)

Question 6

metal microstructure

Answer 6

polycrystalline

- has grains and grain boundareis

Question 7

how do grain and grain boundaries form

Answer 7

liquid metal cools to form points called nuclii

temperature lowers and neucli grow until they hit another one to meet at grain boundaries

Question 8

How do we look at metals

Answer 8

use acid to etch the high energy parts away (neuclei)
etching creates grain contrast depending on the crystal orientation
(leading to different shading)

Question 9

alloys

Answer 9

metal in combination with other metals

consist of single or multiple phases

Question 10

what structures can metals form when they mix

Answer 10

substitutional solid solutions
interstitial solid solutions
inter metallic compounds

Question 11

substitutions solid solutions

Answer 11

different atoms have the same valency with same crystal structure
atomic size within 15%
ions can substitute with each other i.e. fully mix together

Question 12

what does valency mean

Answer 12

bonds

Question 13

interstitial solid solutions

Answer 13

where one solute atom is bigger than another solute atom
solute atoms occupy the space between the bigger solute atoms
there is distortion of the lattuce to accommodate the extra atoms

Question 14

inter metallic compounds

Answer 14

two or more metals combine with a discrete composition or stoichiometric ratio
composed or definite proportions
i.e. ratio similar and different structure

Question 15

what are phases

Answer 15

different crystal structures

Question 16

Alloys

Answer 16

consist of single or mutliple phases

Question 17

What are intermetallic compounds

Answer 17

consitist of multiple phases

Question 18

What are metals held together

Answer 18

metallic onds

Question 19

what are metals usually

Answer 19

polycrystalline and can take up many crystal forms

Question 20

phase diagras

Answer 20

graphical form of the phases in an alloy dependant on composition and temerpature

Question 21

liquids line

Answer 21

separates the liquid from the solid liquid phases

Question 22

phase diagrams

Answer 22

see lecure