This paper reports on the effect of scanning speed on the laser deposited Cu on titanium alloy substrate. The experiments were conducted by varying the scanning speed from 0.3 m/min to 1.2 m/ min while the laser power, the powder feed rate and the gas flow rate were kept constant. The laser deposited Cu were characterized through the evolving microstructure and surface roughness. Dendrites and acicular were much pronounced in the clad area; found to decrease as the scanning speed increases due to the laser interaction time and the cooling rate. These however, influenced the irregularities in the peaks and valleys of the surface texture. The arithmetic mean deviation, Ra were measured and abridged from 6.70 µm to 1.41 µm as the scanning speed was increased from samples DC1 to DC4. The motivation for this work is to improve the surface performance of Ti6Al4V alloy when exposed and attacked by marine microfouling organisms.
The aim of this paper is to study the effect of welding current on the microstructure and the mechanical properties. Material characterizations were conducted on a 6 mm thick plates of type-304 austenite stainless steel, welded by TIG welding process at two different welding currents of 150 A (Sample F3) and 170 A (Sample F4). The tensile strength and the elongation obtained from sample F4 weld were approximately 584 MPa and 19.3 %; which were higher than sample F3 weld. The average micro hardness value of sample F4 weld was found to be 235.7 HV, while that of sample F3 weld was 233.4 HV respectively. Homogenous distribution of iron (Fe), chromium (Cr) and nickel (Ni) were observed at the welded joint of the two samples. The EDS analysis revealed that Fe, Cr, and Ni made up the composition formed at the weld zone. The optimum welding current of 170 A for TIG welding of type-304 austenite stainless steel can be recommended for high-tech industrial applications.
Stainless steel is a family of Fe-based alloys having excellent resistance to corrosion and as such has been used imperatively for kitchen utensils, transportation, building constructions and much more. This paper presents the work conducted on the material characterizations of a tungsten inert gas (TIG)–metal inert gas (MIG) hybrid welded joint of type 304 austenitic stainless steel. The welding processes were conducted in three phases. The phases of welding employed are MIG welding using a current of 170[Formula: see text]A, TIG welding using a current of 190[Formula: see text]A, and a hybrid TIG–MIG welding with currents of 190/170[Formula: see text]A, respectively. The MIG, TIG, and hybrid TIG–MIG weldments were characterized with incomplete penetration, full penetration and excess penetration of weld. Intergranular austenite was created toward transition and heat affected zones. The thickness of the delta ferrite ([Formula: see text]-Fe) formed in the microstructures of the TIG weld is more than the thickness emerged in the microstructures of MIG and hybrid TIG–MIG welds. A TIG–MIG hybrid weld of specimen welded at the currents of 190/170[Formula: see text]A has the highest ultimate tensile strength value and percentage elongation of 397.72[Formula: see text]MPa and 35.7%. The TIG–MIG hybrid welding can be recommended for high-tech industrial applications such as nuclear, aircraft, food processing, and automobile industry.
Surface engineering applications have brought the titanium and its alloys into the limelight in the manufacturing industries such as the aerospace, automobile, marine, chemical processing industry, nuclear power and biomedical. Despite the growths experienced in the use of this material, it is plagued with poor wear behaviour, especially when in contact with other materials during application. In this research work, the reinforcement of titanium alloy (Ti6Al4V) and boron carbide (B 4 C) ceramic powders was employed to form the Ti6Al4V+B 4 C composites. The effect of laser power on the micrograph, microhardness, surface roughness and wear has been investigated. The micrographic evaluation, the geometrical analyses and the effect of laser power on the width and height of deposit, aspect ratio and dilution rate were also evaluated. The highest aspect ratio of 5.31 and dilution rate of 63.81 % was observed in sample MB5 deposited with a laser power of 2400 W. The dry sliding friction and wear conducted using a 10 mm diameter tungsten carbide ball and a normal load of 25 N revealed that sample MB2 produced at a laser power of 1800 W has the lowest wear depth and wear width of 74.6 µm and 1080.77 µm. From the lowest COF attributed by sample MB5, it can be inferred that coefficient of friction does not determine the wear loss due to the sticking of some wear debris to the wear track during sliding action. Thus, other wearing factors are also considered for the wear loss evaluation.However, this composite can be used for the repair of the worm part of a rotating shaft and turbine blades.
—Pure copper was deposited with Ti6Al4V alloy via laser metal deposition (LMD) process to produce Ti6Al4V/Cu composites. This paper reports the effect of powder flow rate (PFR) and gas flow rate (GFR) of laser metal deposited Ti6Al4V/Cu composites. The deposited samples were characterised through the evolving microstructure and microhardness. It was observed that the PFR and GFR have an influence on the percentage of porosity present in the samples. The higher the flow rates of the powder and the gas, the higher the degree of porosity and vice versa. The widmanstettan structures were observed to be finer as the flow rate reduces which in turn causes a decrease in the hardness values of the deposited composites. The hardness values varied between HV381.3 ± 60 and HV447.3 ± 49.
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