TOPIC 3 EXPLORATION.docx

+-----------------------------------------------------------------------+ | **What Is an Alloy?** | | | | **An alloy is a material composed of a metallic base, usually the | | la...

+-----------------------------------------------------------------------+ | **What Is an Alloy?** | | | | **An alloy is a material composed of a metallic base, usually the | | large majority component, and additional metal or non-metal | | components that are added as property modifiers. Alloys are | | manufactured and carefully tuned by experiment to deliver desirable | | properties that are not present in the primary material.** | | | | **Many alloys are made purely of metals, but non-metal additions such | | as Silicon, Sulfur, Carbon, Nitrogen, and other light elements are | | commonly used as property adjusters.** | | | | **What Are Alloys Made Of?** | | | | **Alloys are merged materials composed of a primary base element | | combined with various secondary elements. The base element provides | | the fundamental structure and typically the solubility medium that | | disperses the other components uniformly, while the secondary | | elements are added in specific proportions to adjust and bequeath | | desirable properties of the final material. The resulting alloy | | inherits a summary of the characteristics of all its constituents and | | in many cases, unexpected cooperative gains that none of the | | individual constituents display, leading to selectively improved | | performance.** | | | | **How Are Alloys Made?** | | | | **Alloys are made by smelting and blending the base metal and | | additional elements (metals and/or non-metals) and allowing them to | | cool. The admixing is often performed in the melt, but many | | non-metallic additives can be worked in after initial solidification, | | by various methods. Two primary types of alloys are used; | | substitutional and interstitial alloys.** | | | | **In substitutional alloys, like brass and bronze, the atoms of all | | of the alloying elements are similar in size. The atoms of the | | alloying elements substitute for the same sites the atoms of the base | | material would occupy in its lattice structure. This lends | | distributed property adjustments to the lattice that are intrinsic to | | the metals involved. In most cases the substitution disrupts and | | stresses the lattice, reducing planar slip potential by blocking.** | | | | **In interstitial alloys such as steel, the atoms of the alloying | | elements (Carbon, Silicon, Nitrogen) are smaller and fit in between | | the atoms of the base metal. This placement also acts to disrupt | | slippage and fracture. However, some non-metallic elements such as | | Silicon act as crystal growth triggers, altering the typical crystal | | size to add strength and resilience as more and smaller crystals | | deliver a tougher material.** | | | |   | +-----------------------------------------------------------------------+