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Experimental Research on Flexible Electrode Electrical Discharge Surface Strengthening to Titanium Alloys

Author: XuAnYang
Tutor: LiuZhiDong
School: Nanjing University of Aeronautics and Astronautics
Course: Mechanical Manufacturing and Automation
Keywords: Flexible electrode EDM Titanium alloy Surface hardening Surface roughness Surface hardness
CLC: TG174.4
Type: Master's thesis
Year: 2010
Downloads: 79
Quote: 0
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Abstract

Titanium alloy with a small density, specific strength and stiffness, good anti-corrosion, high temperature mechanical properties and resistance to fatigue and creep properties and hydrogen absorption, superconducting, non-magnetic shape memory, low damping excellent characteristics, but the presence of low hardness, low thermal conductivity, wear resistance, prone to thermal adhesion, flame defects and poor. In order to improve the surface properties of titanium, reinforced by the traditional EDM surface experimental study, the proposed the flexible electrode titanium alloy surface spark strengthening process. This method has the traditional spark surface strengthening advantages and effectively overcome the deposition efficiency in the presence of the conventional spark surface strengthening is low, is not suitable for large area enhancement, on the surface quality of the damaging effects and other shortcomings and deficiencies. The broad adaptability good strengthening effect and surface quality, as well as on the type of surface indicates that this technology has broad application prospects strengthened to provide a new process for the titanium surface. The main work of this paper are as follows: 1) to strengthen the basic principles and the analysis of the problems of the EDM surface, combined with the test requirements, test system to establish a flexible electrode titanium alloy spark surface strengthening. 2) the use of the flexible electrode spark strengthening the surface of titanium alloy TC4 air medium. Tissue composition and mechanical properties of the strengthening layer, hardening layer thickness of the strengthening layer hardness, surface quality, and strengthen the layer of tissue components in the test analysis. The experimental verification of the flexible electrode spark strengthen titanium alloy specimens surface quality, a certain thickness of the strengthening layer, titanium alloy surface hardness titanium alloy surface. 3) the discharge characteristic of the titanium surface of the flexible electrode spark strengthening, to prove that the discharge is an arc discharge, and the time of contact of the wire electrode with the surface of the test piece is far less than the pulse width in a pulse width, there will be a plurality of wire electrode with the surface of the test piece is subjected to arc discharge, the discharge state in the jump between the arc discharge and short-circuit state. Single pulse energy is dispersed in the multi-point discharge, is conducive to maintaining the enhanced surface quality. 4) to study the impact of factors to strengthen the quality of the layer surface, the strengthening layer thickness and surface hardness. Surface hardness with the improvement of the discharge energy (average current, and pulse width) to improve the surface roughness value is increased with the improved discharge energy, and surface quality. Flexible electrodes on the surface of the titanium alloy specimens coated grinding action, help to improve to strengthen the quality of the surface. 5) taking into account the surface roughness values ??of the reinforcing layer and the surface hardness value, it can be used to meet requirements obtain high hardness, and the thicker the thickness of the reinforcing layer of electrical parameters and other strengthening parameters in order to obtain a higher hardness and a relatively thick reinforcing layer, while increase strengthen the efficiency, and the use of small electrical parameters and other strengthening parameters for renovations to the enhanced surface, to reduce surface roughness and improve and strengthen the surface quality of the surface and a dense, so that the specimen to strengthen the surface to obtain a good surface quality while having high hardness. 6) the strengthening layer corrosion and wear resistance and its impact factors were studied. Proof titanium surface through flexible electrode spark strengthening treatment, its abrasion resistance and corrosion resistance is significantly improved.

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > Metal corrosion protection,metal surface treatment > Corrosion control and protection > Metal surface protection technology
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