MORPHOLOGICAL, MICRO-MECHANICAL, CORROSION AND IN VITRO BIOACTIVITY INVESTIGATION OF SUPERFICIAL LAYER FORMATION DURING WIRE ELECTRICAL DISCHARGE MACHINING OF Ti-6Al-4V ALLOY FOR BIOMEDICAL APPLICATION

Author(s):  
SANDEEP MALIK ◽  
VINEET KUMAR

In this work, the experimental investigation of the surface integrity and biomechanical properties of the superficial layer obtained by wire electrical discharge machining (W-EDM) of Ti-6Al-4V alloy for biomedical application has been carried out. The surface morphology and elemental composition of the superficial layer have been investigated by field-emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) techniques. The micro-mechanical behavior in terms of compressive strength and surface hardness was studied using the micro-pillar and nano-indentation technique. The corrosion resistance and in vitro bioactivity have been investigated using electrochemical and immersion test. Morphological analysis showed that surface morphology and superficial layer thickness were affected by peak current, pulse-duration and pulse-interval. The niobium (Nb)-rich layer was developed in superficial layer zone. The low peak current (3–6[Formula: see text]A), low pulse-duration (5–10[Formula: see text][Formula: see text]s) and high pulse-interval ([Formula: see text]s) have been recommended for better surface morphology and thin superficial layer (ranging from 4–6[Formula: see text][Formula: see text]m) free from surface defects. The micro-pillar and nano-indentation results showed that the superficial layer comprised of a brittle structure that improved the mechanical properties of the layer and the compressive strength was measured to be 1198 MPa. The corrosion resistance analysis revealed that the Nb-rich layer in the superficial layer improved the corrosion resistance and bioactivity. Excellent apatite growth has been found in the W-EDM-processed zone. The W-EDM can be used for the biomedical industry as a potential surface engineering technique.

2012 ◽  
Vol 472-475 ◽  
pp. 2013-2017
Author(s):  
Chao Jiang Li ◽  
Yong Feng Guo ◽  
Ji Cheng Bai ◽  
Ze Sheng Lu ◽  
Chuan Chen

The wire electrical discharge machining (WEDM) has been widely used in the field of metal cutting, mold industry, aerospace and so on. However, in the discharge machining, it is very important to restrain the wire-tool vibration for the improvement of machining accuracy. In this paper, it is created a model of the wire vibration with double-ended fixed, established the differential equation of vibration, and derived its full theoretical solution to analysis the vibration factors. Simulations of the wire vibration with ANSYS Transient dynamics analysis were given. An orthogonal design of the wire vibration using L9 orthogonal table was made, and the experiment found that minimize the servo voltage, reduce the pulse width, and select the appropriate wire tension and pulse interval, which can reduce the wire vibration.


2015 ◽  
Vol 227 ◽  
pp. 479-482
Author(s):  
Jeremiasz Krzysztof Koper ◽  
Jarosław Jakubowicz

The paper describes anodic oxidation of titanium surface in a potential range from 30 to 240 V in a 2M H3PO4electrolyte with the addition of 0÷2 % HF. The aim of the treatment was to form titanium oxide with a developed, rough morphology, useful for biomedical application. The morphology of the anodically oxidized samples was examined using SEM and AFM. The phase structure of the oxides was determined by XRD. One of the main parameters determining the suitability of that material for biomedical application is the corrosion resistance in an environment comparable to human body (Ringer’s solution). It has been observed that corrosion resistance of the anodized surfaces increases with the increase of the anodizing voltage for the samples oxidized in an electrolyte containing 0 % and 0.2 % HF. In electrolytes with the addition of 1 % and 2 % HF an inverse relationship was observed. The corrosion resistance of all tested surfaces was sufficiently high for the application as a biomaterial. The most promising anodizing treatment, providing best surface morphology and corrosion resistance was performed at 210 V in a 2M H3PO4+ 1 % HF electrolyte.


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