Time The Third Dimension
The TTT Diagram
The Kinetics of Phase Transformations for Nonmetals
at different cooling rates
35 wt% Ni-65 wt% Cu alloy
The simplest repeat structural unit of a crystal solid at the atomic or molecular level
The complete structure can be created by the repeated stacking of unit cells
Lattice constants: a, b, c, , ,
Figure 3.2 Geometry of a general unit cell.
2. [7 points] The unit cell of a hypothetical metal is shown below, where = = = 90.
a) To which crystal system does the unit cell belong? [1 point]
b) What would this crystal structure be called? [1 point]
c) Calculate the density (g/cm3) of the material,
Figure 10.22 The cooling rate for the Jominy bar (see Figure
10.21) varies along its length. This curve applies to virtually all
carbon and low-alloy steels.
Figure 10.24 Hardenability curves for various steels with the same
carbon content (0.40 w
Chemical (or compositional) imperfections
Pure quartz (SiO2)
Some free silicon
ChE241-Prof. Y.Li Iron and other transition metal impurities
Trace amounts of titanium, iron, or
Lattice positions can be described by a set of numbers (coordinates) expressed as
fractions or multiples of unit cell dimensions.
Figure 3.22 Notation for lattice positions.
A unit cell can be translated periodicall