Ashutosh Pattanaik

The effect of environmental aging conditions on the structural and mechanical properties of fly ash (FA) filled epoxy composites with four different volume fraction of FA (i.e. 0.1, 0.2, 0.3 and 0.4) has been investigated under four aggressive aging environments and aging periods. The crystallite size and microstrain of crystalline particle in the composite matrix is quantified from XRD analysis. The 10% FA filled epoxy composite under fuel solution retains the higher order of crystallinity and glass transition temperature. It is observed that the void content and actual density of composites decreases with increasing FA content. The mechanical behavior of FA epoxy composite deteriorated with increasing aging duration and reinforcement percentage. 10% FA-containing specimen gives the highest mechanical properties under fuel environment for any given aging duration. The 20% FA filled epoxy composite can also be used in low load bearing applications.

Spheroidal graphite cast iron (SG iron) is the most preferable member of cast iron family due to its strength and toughness along with good tribological properties. SG iron specimens with annealed and martensitic matrix were subjected to dry sliding wear condition and the system response was correlated to matrix microstructure. Respective microstructure was obtained by annealing and quench and tempering heat treatment process for an austenitizing temperature of 1000°C. Specimens were subjected to Ball on plate wear tester under 40N, 50N, 60N load for a sliding distance of 7.54m. Except for quench and tempered specimen at 50N, weight loss was observed in every condition. The wear surface under optical microscope reveals adhesive mechanism for as-cast and annealed specimen whereas delaminated wear track feature was observed for quench and tempered specimen. I. Introduction Spheroidal graphite cast iron (SG iron) or ductile iron (DI) unlike every other cast iron has graphite in the form of spheroids which act as crack arrester, due to which it possesses higher strength and toughness along with better wear resistance. Furthermore it has been proved that the properties of SG iron can be improved by application of suitable heat treatment process leading to transformation of as-cast ferritic or ferritic/pearlitic matrix into pearlitic, martensitic and bainitic. Austempered ductile iron is one of the most favorable materials among all other type because of its excellent strength, toughness, wear resistance, fatigue strength and fracture toughness [1-8]. Tribological investigation carried out on austempered SG iron with varying austempering time and temperature, reported increased wear resistance with increasing austempering temperature and time along with increased hardness during wear due to the bainitic ferrite which is less prone to thermal instability than martensite, might undergo strain hardening [9, 10]. Tempering treatment on ductile iron with boron increased the wear resistance but with increasing boriding time wear rate of boro-tempered ductile iron decreased [11]. Apart from alloying element and heat treatment graphite nodule size and distribution affects the wear resistance of SG iron. According to a study by Sugishita and Fujiyoshi [12] and Zimba et.al [13] presence of large size graphite nodules reduces the wear rate by acting as lubricating agent.

Industrial waste like fly-ash is mainly used as a good building material due to its low
weight. But the main disadvantage of these bricks is its low compressive strength. So, a
lot of research is going on to increase the strength of these bricks. Normal clay is used
for making of bricks in a cheaper sense. So, a research is carried out to develop a new
systematic procedure to produce a new type of brick which will have higher compressive
strength than the normal clay bricks. Here the fly-ash is mixed with clay at different
compositions, sintered at different temperatures and their microstructural analysis has
been carried out to find out a solution to enhance its property.

New technologies demand newer manufacturing techniques, but most products still require traditional manufacturing processes and carry along their inherent environmental implications. Developing countries like India, which is entering mass production, in particular, are taking on an increased environmental burden in manufacturing. In view of this, there is a real need to study the environmental concerns of the conventional manufacturing technology. Machining is a material removal process that typically involves cutting of metals using various cutting tools. It is a process that is particularly useful due to its high dimensional accuracy, flexibility of process and cost-effectiveness in producing limited quantities of parts. Among manufacturing processes, machining is unique in that it can be used both to create products and to finish products. However, since it is inherently a process that removes material, machining can be wasteful in its use of both materials and energy. The present paper focuses on investigating various aspects of machining process from environmental perspective assuming a system-level, environmentally-focused analysis of machining.

Nanostructured tungsten (W) based alloy with nominal composition of W 80 Ni 10 Nb 10 (in wt. %) was synthesized by mechanical alloying of elemental powders of tungsten (W), nickel (Ni), niobium (Nb) in a high energy planetary ball-mill for 20 h using chrome steel as grinding media and toluene as process control agent followed by compaction at 500 MPa pressure for 5 mins and sintering at 1500°C for 2 h in Ar atmosphere. The phase evolution and the microstructure of the milled powder and consolidated product were investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The crystallite size of W in W 80 Ni 10 Nb 10 powder was reduced from 100 µm at 0 h to 45.6 nm at 10 h and 34.1 nm at 20 h of milling whereas lattice strain increases to 0.35% at 20 h of milling. The dislocation density shows sharp increase up to 5 h of milling and the rate of increase drops beyond 5 to 20 h of milling. The lattice parameter of tungsten in W 80 Ni 10 Nb 10 expanded upto 0.04% at 10 h of milling and contracted upto 0.02% at 20 h of milling. The SEM micrograph revealed the presence of spherical and elongated particles in W 80 Ni 10 Nb 10 powders at 20 h of milling. The particle size decreases from 100 µm to 2 µm with an increase in the milling time from 0 to 20 hours. The crystallite size of W in milled W 80 Ni 10 Nb 10 alloy as evident from bright field TEM image was in well agreement with the measured crystallite size from XRD. Structure of W in 20 h milled W 80 Ni 10 Nb 10 alloy was identified by indexing of selected area diffraction (SAD) pattern. Formation of NbNi intermetallic was evident from XRD pattern and SEM micrograph of sintered alloy. Maximum sinterability of 90.8% was achieved in 20 h milled sintered alloy. Hardness and wear study was also conducted to investigate the mechanical behaviour of the sintered product. Hardness of W 80 Ni 10 Nb 10 alloy reduces with increasing load whereas wear rate increases with increasing load. The evaluated hardness value in the present study for all loads is lower than the literature reported hardness of nanostructured W.

Spheroidal graphite cast iron is one of the most favorable materials in cast iron family due to its wide range of mechanical and tribological properties. In the current research priority is given towards the investigation of wear system response of spheroidal graphite cast iron subjected to various heat treatment conditions. Pearlitic/ferritic and upper bainitic matrix was obtained through normalizing and austempering treatment for an austenitizing temperature of 1000°C. Dry sliding wear test was performed at 10N, 20N, 30N for a sliding distance of 7.54m. With increase in load weight loss was observed for as-cast specimen whereas normalized specimen showed very less weight loss with increasing load. On the other hand the austempered specimen observed to lose weight when operated at 10N, whereas at 20N and 30N drastic gain in weight was observed.