TITLE:
Analysis of Fatigue and Microhardness in Metallic Powder Mixed EDM
AUTHORS:
Alexis Mouangué Nanimina, Nandiguim Lamaï, Djimako Bongo, Togdjim Jonas, Bonaventure Danoumbé, Ahmad Majdi Abdul-Rani
KEYWORDS:
PMEDM, Fatigue, Micro-Hardness, Discharge Current, Gap Voltage, ON-Time
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.10 No.10,
October
13,
2020
ABSTRACT: The objective of this work research is to investigate the potential of
using metallic powder mixed with electrical discharge machining (EDM)
dielectric when machining hard electrically conductive materials. Nowadays, the
development of industries requires hard materials for various applications.
Machining the hard materials using the traditional processes lead to tool break
and poor machined product. Even when the conventional EDM can machine hard material as long as it is electrically conductive materials,
the machined parts still present drawbacks. Metallic powder mixed with EDM
dielectric (PMEDM) was hypothesized to improve the machined part. The presence
of metallic powder ensures uniform distribution of spark and the electrical
density of the spark decreases which reduces craters, cracks and voids on
machined surface. The transfer and deposit of alloying elements during powder
mixed electrical discharge machining improve the machined surface properties
particularly micro-hardness and fatigue. Discharge current (IP), gap voltage
(GapV), ON-time (ON) and aluminum powder are selected as machined variable
parameters and the output responses are fatigue performance, micro-hardness and
surface topography. The workpiece material selected is molybdenum high speed steel. Micro-hardness was
determined using micro-hardness tester device. The fatigue performance was
determined using empirical equation. Analysis of material transfer was done
using energy dispersive spectroscopy (EDS) attached to FESEM. EDS analysis
involves the generation of an X-ray spectrum from the entire scan area of the
SEM. The use of PMEDM improved the
fatigue, the micro-harness and the machined surface morphology as the
above-mentioned parameters increased.