ENGINEERING MATERIALS

Engineering Materials

Engineering Materials

Q 1

Mechanical Working of Metals

Mechanical working of a metal is plastic deformation performed to change dimensions, properties, and/or surface conditions. Plastic deformation below the recrystallization temperature is called cold working.

Powder Processing

Powder processing is an integral part in the fabrication of ceramic pieces with specific microstructural futures. Even the most ideal powder choice will not guarantee that the desired ceramic properties can be achieved if the powder processing is neglected or badly designed.

The process of sintering starts with the material in powder form and is used for a wide variety of materials, especially those with properties which preclude shaping by melting and casting (Eberhart 2003 362-531).

Extrusion Process

The extrusion process is used most frequently to form plastic and aluminium parts or products. However, ceramics, heavier metals or alloys, and foods such as pasta, are also shaped and manufactured through the extrusion process. Essentially, as long as a material can be easily liquefied, it can be extruded.

Extrusion processing is distinct from stamping or molding, for instance, in that the extruded material will form intricate, strong, and durable fittings, parts, and pieces from brittle stock that is difficult to shape through stamping, bending, or hammering. Intricate cross-sections such as hollow tubes or solid pieces, or rods with flanges or wings are far easier to manufacture through the extrusion process (Wachtman 2006 529-663).

Joining

A material joining is a general term encompassing many different processes, including various methods of welding, brazing, soldering, adhesive bonding and even some kinds of mechanical fastening. Advances in the technology of these processes enable a wide variety of materials, such as metals, ceramics, polymers, composites and electronic materials, to be joined in ways that maximize reliability and minimize cost.

Materials Joining Engineering (MJE) is a hybrid discipline that combines the fundamental principles of materials, mechanical, structural and electrical engineering, adapting them to the development and application of joining technology (Mathews & Rawlings 1999 7-21).

Welding

Proprietary electro-optic techniques provide video which is virtually free of any brightness or incandescence coming from the scene. When viewing hot steel, the glow is eliminated and surface defects on continuous cast or rolled products are revealed.

Casting

Casting is a manufacturing process by which a liquid material is usually poured into a meld, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the meld to complete the process. Casting materials are usually metals or various cold setting materials that cure after mixing two or more components together; examples are epoxy, concrete, plaster and clay (Walker 1999 635-725). Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods.

Q 2

Crystalline Structure

Crystals have been studied using x-rays, which excite signals from the atoms. The signals are of different strengths and depend on the electron density distribution about atomic cores. Light atoms give weaker signals and hydrogen is invisible to ...