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Composite material constitute of different materials to have better characteristics than traditional materials. Material properties such as physical, chemical and mechanical properties can be tailored in composite material based on requirements. This advantage extends the composite material applications in the field of human implants. Traditional metals or ceramics have certain limitations after the implantation in human body, because of its inheriting properties with biological tissue. These limitations can be eradicated by the composite material; it makes composites to fabricate implant for biomedical applications. The new research works enhance the composite materials to mimic the natural bone, biological functions and tissue characteristics. Human tissue and bone are naturally graded from the core side, functionally graded material (FGM) implant overcome some limitations of composite materials. FGM implants elastic modulus can be tailored as like a composite material, its biological functions similar with natural one. Other biological parameters such as corrosion, wear resistance and fracture toughness are considered when designing the implant. This article discusses composite material advantage and limitations of both composite and FGM implants.

The machining of extremely hard material in conventional machining requires high energy. Therefore stress-free, burr-free, and high-accuracy machining technique like Electro Chemical Micro Machining (ECMM) with extra features is recommended. To improve efficiency, various electrolytes such as Magnet Associated Electrolytes (MGAE), Metal Particle Mixed Electrolytes (MPME), and Carbon Pellets Mixed Electrolytes (CPME) are employed. The micro-holes were drilled over the work material MONEL 400 alloy. The parameters for the studies are electrolyte type, concentration (g/l), machining voltage (V), and duty cycle (%). The responses of ECMM are estimated through material removal rate (MRR) in ?m/sec and overcut in ?m. The results are optimized using Multi-objective optimization based on ratio analysis (MOORA) and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR). Both techniques produce the same optimal parameter, 18th experiment CPME, 50% duty cycle, 11 V machining voltage, and 28 g/l electrolyte concentration. It is the best optimal parameter solution for machining. According to the ANOVA table of both, the type of electrolyte plays a 62.6 % and 60.37% contribution, respectively, to machining performance. Furthermore, the scanning electron microscope (SEM) image analysis perused on the micro holes to extend the effect of different electrolytes on machining surfaces.