In this chapter, low elastic modulus porous Mg-Zn-Mn-(Si, HA) alloy was fabricated by mechanical alloying and spark plasma sintering technique. The microstructure, topography, elemental, and chemical composition of the as-sintered bio-composite were characterized by optical microscope, FE-SEM, EDS, and XRD technique. The mechanical properties such as hardness and elastic modulus were determined by nanoindentation technique. The as-sintered bio-composites show low ductility due to the presence of Si, Ca, and Zn elements. The presence of Mg matrix was observed as primary grain and the presence of coarse Mg2Si, Zn, and CaMg as a secondary grain boundary. EDS spectrum and XRD pattern confirms the formation of intermetallic biocompatible phases in the sintered compact, which is beneficial to form apatite and improved the bioactivity of the alloy for osseointegration. The lowest elastic modulus of 28 GPa was measured. Moreover, the as-sintered bio-composites has high corrosion resistance and corrosion rate of the Mg was decreased by the addition of HA and Si element.
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Describe Metallic biomaterials like stainless steel, cobalt chromium, titanium and its alloys were used for hard tissue replacement for the decade (Niinomi et. al., 2012; Geetha et. al., 2009; Bartolo et. al., 2012; Vaccaro et. al., 2003; Bartolo et. al., 2009). The main drawback with these materials are used as permanent implants, thus after bone healing the implants were taken off from the body by additional surgery causes an increase in costs to the healthcare, as well as anxiety to the patient (Prakash et. al., 2016; Prakash et. al., 2015; Prakash et. al., 2017). In the current, the magnesium base alloys and bio-composite have gained much attention of researchers for the design and development orthopedic implants due to their high biodegradability and unique combination of mechanical properties such as low elastic modulus and high strength (Staiger et. al., 2016). Till date no perfect magnesium alloy available that possessed the adequate putrescible integrity to corrosion for a certain period of bone healing (Vahidgolpayegani et. al., 2017). The major drawback of Mg alloy, which hampers their eminent utility, is their rapid corrosion rate in the human body (Uddin et. al. 2015). Through decades past, numerous procedures and techniques were practiced to retard the corrosion rate, predominantly, to delay the degradation of the Mg alloy at a pace that matches bone healing (Cui et. al., 2008; Hassel et. al., 2007; Salahshoor et. al., 2013). The mechanical alloying of the element is the most promising technique yet to control the corrosion rate and to improve the mechanical properties (Uddin et. al. 2017). Till date various alloying elements such as zinc (Zn), aluminium (Al), silver (Ag), yttrium (Y), zirconium (Zr), neodymium (Nd), silicon (Si), and manganese (Mn) have been used as alloying elements to enhance the mechanical properties and corrosion behavior of Mg alloy. In this regard, various Mg-based alloys such as Mg–CA binary alloy (Staiger et. al., 2006), Mg–Zn (Xu et. al., 2007), Mg–Sr (Li et. al., 2008), Mg-Mn-Zn (Xu et. al., 2008; Zhang et. al., 2009), Mg-Zn-Y (Zhang et. al., 2008) and Mg-Zn-Mn-CA alloys (Zhang et. al., 2008) and much more had been developed. Among them, the implant made by the alloying of Ca, Mn, Z, and Si elements improved the mechanical properties and corrosion resistance (Witte et. al., 2007). In reality, there are only a few elements including Ca, Mn, Zn, and Si that can be accommodated in the human body and can also retard the biodegradation of Mg alloys. The element Ca and Zn are the abundant minerals necessary for the bone ingrowth in human and one of the most favoring alloying elements used for magnesium alloys (Khanra et. al., 2010, Gu et. al., 2010; Ye et. al., 2010; Zhao et. al., 2011; Viswanathan et. al., 2013). The manganese (Mn) decreases the corrosion rate of the Mg-alloys.