Alloys

Materials Science and Engineering

Alloys

INDEX

INTRODUCTION…………………………………………………………………………2

BASIC CONCEPTS OF ALLOYS………………………………………………….…….3

What is an Alloy?...................................................................................................................3

Alloy processing….…………………………………………………………………………3

Classification of alloys………………………………………………………………………7Solid Solutions………………………………………………………………………………7

FERROUS ALLOYS: STEELS AND CAST IRONS……………………………………...8

Steels and cast irons…………………………………………………………………………8

Treatment of steels and cast irons…………………………………………………………...8
--Iron and carbon phase diagram
--Steel Producing…………………………………………………………………………...13

Designation and classification……………………………………………………………...15

Properties ofsteels…………………………………………………………………………16

NON-FERROUS ALLOYS……………………………………………………………….17

Non-ferrous alloys………………………………………………………………………….17

Aluminum alloys…………………………………………………………………………...18

Examples of other alloys…………………………………………………………………...19
-Magnesium alloys…………………………………………………………………………19
-Copper alloys……………………………………………………………………………...21
-Titanium alloys……………………………………………………………………………22SUPERALLOYS…………………………………………………………………………..26

REFERENCES……………………………………………………………………………..28

INTRODUCTION

Just about every single piece of metal that you come into contact with on a daily basis is an alloy of some kind. There are very few pure metals used for anything. Alloys are made with far superior characteristics than the raw metals they are made from. Steel is a obvious example (an alloy of iron).
Uses for alloys are limitless, and include an extensive range ofmarine, medical, military, commercial, industrial, residential and manufacturing applications. Even brass and bronze, two of the earliest alloys produced, still have extensive uses, and remain in high demand.
Alloying is not always done to produce a 'superior' material, but to produce materials having a derired requirement in the industry or elsewhere. A classic case is of lead solder(containing lead & tin), in which the melting point of the constituent elements are lowered, not necessarily a desirable property.

Alloying can be carried out using hot press method (a sheet of material is sandwiched with alloying material), rolling the heated base metal in a drum full of alloying metal powder, using hot spraying, galvanizing (dipping the base in a molten solution of alloying material)etc.
Sometimes the alloying material is addded in small proportions to the molten base metal (eg, in production of different types of steel). But what kind of materials are alloys? How are they made? How can we analyze the properties of an alloy? And why is its use important?, these are questions we will following give a answer.

BASIC CONCEPTS OF ALLOYS

Combining one metal with othermetal(s) or non metal(s) often enhances its properties. For example, steel is stronger than iron, its primary element. The physical properties, such as density, reactivity, Young's modulus, and electrical and thermal conductivity, of an alloy may not differ greatly from those of its elements, but engineering properties, such as tensile strength and shear strength may be substantially different fromthose of the constituent materials, this is defined as an alloy.

Alloy: An alloy is a partial or complete solid solution of one or more elements in a metallic matrix. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may be homogeneous in distribution depending on thermal (heat treatment) history. Alloys usually havedifferent properties from those of the component elements.

This is sometimes due to the sizes of the atoms in the alloy, since larger atoms exert a compressive force on neighboring atoms, and smaller atoms exert a tensile force on their neighbors, helping the alloy resist deformation. Sometimes alloys may exhibit marked differences in...