Constitution of Alloys

Question 1

a substance that has metallic properties and is composed of two or more chemical elements, one of which is a metal

Answer 1

alloy

Question 2

what are the two alloy systems

Answer 2

binary alloy system, ternary alloy system

Question 3

• made up of two elements

Answer 3

binary alloy system

Question 4

• made up of three elements

Answer 4

ternary alloy system

Question 5

What are the classification of alloys?

Answer 5

homogenous, mixture

Question 6

consist of single phase

Answer 6

homogenous

Question 7

combination of several phases

Answer 7

mixture

Question 8

what are the possible phases in the solid state

Answer 8

pure metal, intermediate or compound, solid solutions

Question 9

Under equilibrium conditions, all metals exhibit a definite melting or freezing point.
*under equilibrium conditions - implies extremely slow heating and cooling

Answer 9

pure metal

Question 10

phases whose chemical compositions are intermediate between the two pure metals and have crystal structures different from those of the pure metals

When a compound is formed, the elements lose their individual identity and characteristic properties to a large extent.

Answer 10

intermediate or compound

Question 11

cooling curve for a compound

Answer 11

congruent melting phase

Question 12

what are the most common intermediate alloys

Answer 12

Intermetallic Compounds or Valency Compounds, Interstitial Compounds, Electron Compounds,

Question 13

formed between chemically dissimilar metals and have strong bonding with nonmetallic properties

Answer 13

Intermetallic Compounds or Valency Compounds

Question 14

formed between transition metals such as Sc, Ti, W, Fe, Ta with H, O, C, Ni, B - metallic in properties with high melting points and hard

Answer 14

Interstitial Compounds

Question 15

formed between systems with similar lattice structures and definite ratio of valence electrons to atoms

Answer 15

Electron Compounds

Question 16

have properties resembling those of solid solutions such as wide range of composition, high ductility and low hardness

Answer 16

Electron Compounds

Question 17

• a solution in the solid state and consists of two kinds of atoms combined in one type of space lattice
• solidify over a range in temperature

Answer 17

Solid Solutions

Question 18

What are the types of solid solutions?

Answer 18

Substitutional Solid Solution, interstitial solid solution

Question 19

the atoms of the solute substitute for atoms of the solvent in the lattice of the solvent

Answer 19

Substitutional Solid Solution

Question 20

• formed when atoms of small atomic radii fit into the spaces or interstices of the lattice structure of the larger solvent atoms (atomic radii of less than 1 angstrom such as H, B, C, N, O)
• differs from interstitial compounds in that the amount of smaller atoms required to form the compound is greater than the amount that may be dissolved interstitially
• have very limited solubility and are of little importance

Answer 20

Interstitial Solid Solution

Question 21

Factors under substitutional solid solution

Answer 21

Crystal-structure , relative size, chemical affinity, relative valence

Question 22

favorable when the difference in atomic radii is greater than 8%and less than about 15%

Answer 22

Relative-size

Question 23

favorable when the difference in atomic radii is greater than 8%and less than about 15%

Answer 23

Relative-size

Question 24

the farther apart the elements in the periodic table, the greater it is

Answer 24

Chemical-affinity

Question 25

metal of lower valence tends to dissolve more of a metal of higher valence than vice versa

Answer 25

relative valence