Theses and Dissertations @ UNI

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Open Access Dissertation

Abstract

Wear and corrosion are the two factors that make utilization of metals very costly. Extraordinary amount of time and money is spent to replace metallic parts affected by either wear or corrosion. Cast iron that is used very widely in a host of different industrial products is one such metal. Among the various methods used to improve the properties of metals, production of amorphous metals is highly noticeable. This process is done by treating the base metal in a certain technique which produces a metal that is more resistant to wear and corrosion. This study was conducted to examine the prospect of forming a metallic glass layer on the surface of gray cast iron by adding boron, silicon and cobalt; coupled with the utilization of an industrial carbon dioxide (CO$\sb2$) laser. Three different mixing ratios of the aforementioned alloying elements as well as four different groove sizes on the surfaces of the samples were used. Determination of the characteristics of the laser-formed layers on the surfaces of the samples were conducted by the utilization of x-ray diffraction techniques, mechanical testing, Rockwell hardness testing method, as well as metallographic examinations. The collected test results led to the conclusion that the formation of amorphous metal on the surface of gray cast iron is possible and practical when certain percentage of mixing ratios of boron, silicon and cobalt are used and lased by a 1300 watts industrial CO$\sb2$ laser. Furthermore, the hardness results indicated that a considerably higher degree of hardness resistivity, up to 70 HRC is achievable on the surface of a gray cast iron that has a hardness resistivity of 32 HRC. The micrographical analysis of the formed layers showed textures of a super-saturated structure that presented a high degree of resistivity to both wear as well as corrosion. Boron content attributed to achieving of a high degree of hardness. Particularly when mixed with cobalt and silicon, in the ratio of up to 40% boron content, improved the hardness number directly. Beyond the 40% ratio, the effect of boron on the hardness improvement was not very significant. Three geometrically shaped grooves were machined on the surface of each specimen. Each shape was machined in four different depths on four different specimens. The depth of the lased areas ranged from 0.45mm to 2.15mm.

Year of Submission

1991

Degree Name

Doctor of Industrial Technology

Department

Department of Industrial Technology

First Advisor

Mohammad F. Fahmy (Advisor)

Date Original

8-1991

Object Description

1 PDF file (ix, 129 pages)

Language

EN

File Format

application/pdf

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