Laser surface treatment was carried out on AISI 416 machinable martensitic stainless steel containing 0.225 wt.% sulfur. Nd:YAG laser with a 2.2-KW continuous wave was used. The aim was to compare the physical and chemical properties achieved by this type of selective surface treatment with those achieved by the conventional treatment. Laser power of different values (700 and 1000 W) with four corresponding different laser scanning speeds (0.5, 1, 2, and 3 m·min−1) was adopted to reach the optimum conditions for impact toughness, wear, and corrosion resistance for laser heat treated (LHT) samples. The 0 °C impact energy of LHT samples indicated higher values compared to the conventionally heat treated (CHT) samples. This was accompanied by the formation of a hard surface layer and a soft interior base metal. Microhardness was studied to determine the variation of hardness values with respect to the depth under the treated surface. The wear resistance at the surface was enhanced considerably. Microstructure examination was characterized using optical and scanning electron microscopes. The corrosion behavior of the LHT samples was also studied and its correlation with the microstructures was determined. The corrosion data was obtained in 3.5% NaCl solution at room temperature by means of a potentiodynamic polarization technique.

Purpose The purpose of this paper is to print a thermolabile drug-containing tablet using the fused deposition modeling (FDM) technique and analyze its mechanical, pharmaceutical and environmental feasibility using a variety of tests. Design/methodology/approach Ascorbic acid (Vitamin C) is the thermally-sensitive drug impregnated into polyvinyl alcohol excipient using ethanol-water mixture and printed by an FDM printer by varying three parameters without using any external stabilizing agent. Afterward, Taguchi analysis has been performed on these parameters to recognize the significant factors and interactions. Besides this, a regression model has been obtained based on the dissolution data. Various thermo-mechanical and pharmaceutical tests have been carried out to confirm the feasibility. Finally, a life cycle assessment (LCA) analysis has been carried out to compare it with the existing tableting method by considering the environmental impacts. Findings The dissolution profile was found to follow the Korsmeyer-Peppas model, where the drug release occurred both by dissolution and erosion. Further, the infill percent has been found as the most significant parameter. The characterization tests and imaging outputs proved the fidelity of this attempt. Finally, the three-dimensional printed method was found to be more environmentally sustainable than the existing conventional tableting process. Originality/value LCA on a printed tablet is a one-of-a-kind attempt. Thus, this research attempt delivered another approach to print personalized tablets at a temperature lower than prescribed temperatures with required release behavior and can contribute toward the quest of sustainable personalized medication.

Laser cladding process was performed on a commercial Ti-6Al-4V (α + β) titanium alloy by means of tungsten carbide-nickel based alloy powder blend. Nd:YAG laser with a 2.2-KW continuous wave was used with coaxial jet nozzle coupled with a standard powder feeding system. Four-track deposition of a blended powder consisting of 60 wt % tungsten carbide (WC) and 40 wt % NiCrBSi was successfully made on the alloy. The high content of the hard WC particles is intended to enhance the abrasion resistance of the titanium alloy. The goal was to create a uniform distribution of hard WC particles that is crack-free and nonporous to enhance the wear resistance of such alloy. This was achieved by changing the laser cladding parameters to reach the optimum conditions for favorable mechanical properties. The laser cladding samples were subjected to thorough microstructure examinations, microhardness and abrasion tests. Phase identification was obtained by X-ray diffraction (XRD). The obtained results revealed that the best clad layers were achieved at a specific heat input value of 59.5 J·mm−2. An increase by more than three folds in the microhardness values of the clad layers was achieved and the wear resistance was improved by values reaching 400 times.

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