Lecture note 14 (10-20-2011)

Lecture note 14 (10-20-2011) - MAE 581 Advanced Materials...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1 MAE 581 Advanced Materials Science Lecture note 14 Phase equilibrium and structure Two-phase equilibria Solid solubility is a feature of many metallic and ceramic systems, being favored when the components have similarities in crystal structure and atomic (ionic) diameter. Such solubility may be either extended (continuous) or limited. The former case is illustrated by the binary phase diagram for the nickel–copper system (Figure 2.11) in which the solid solution ( α ) extends from component to component. In contrast to the abrupt (congruent) melting points of the pure metals, the intervening alloys freeze, or fuse, over a range of temperatures which is associated with a univariant two-phase ( α +liquid) field. This ‘pasty’ zone is located between two lines known as the liquidus and solidus. (The phase diagrams for the Ni–Cu and MgO–FeO systems are similar in form.) Solid solubility in binary alloys: continuous, same phase in both components at low temperature. Solid solubility in binary alloys: continuous, a univariant two-phase may exist in both components at high temperature. Let us consider the very slow (equilibrating) solidification of a 70Ni–30Cu alloy . A commercial version of this alloy, Monel , also contains small amounts of iron and manganese. It is strong, ductile and resists corrosion by all forms of water, including sea water (e.g. chemical and food
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 4

Lecture note 14 (10-20-2011) - MAE 581 Advanced Materials...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online