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The current work focuses on the fabrication of high-molecular-weight stereocomplex poly(lactic acid)/nanohydroxyapatite (sPLA/n-HAP)-based bionanocomposite for three-dimensional (3D)-printed orthopedic implants and high-temperature engineering applications. To achieve the same, n-HAP is grafted with poly(d-lactic acid) (PDLA) via in situ ring-opening polymerization of d-lactide, followed by blending with poly(l-lactic acid) (PLLA), which yields sPLA/n-HAP biocomposite with improved storage modulus even at temperatures higher than 140 °C. X-ray diffraction and calorimetric analysis ensure the presence of 100% stereocomplex crystallites of biocomposite along with significant improvement in the melting temperature (∼227 °C). Noteworthy improvements in the mechanical and gas-barrier properties of the developed biocomposites are achieved due to the uniform dispersion of n-HAP (∼60 nm) confirmed by morphological studies. An unusual improvement in elongation at break (∼130% at 1 wt % HAP loading) makes this composite a toughened material. However, the tensile strength is improved by ∼16%, whereas oxygen permeability and water vapor transmission rate are found to reduce by ∼48 and ∼34%, respectively. Interestingly, the developed material is processed as monofilament, followed to 3D printing to yield a middle phalanx bone as a representative example of orthopedic implants. In vitro studies reveal that cell adhesion and proliferation on the surface of the developed biocomposite support its biocompatible nature. This signifies the possible future aspects of the material in commercial biomedical and high-temperature engineering applications.

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The quality of surface is one of the significant parameters which affects the life and functionality of any product. Many products require nano-level surface finish as their functional indispensability. Those processes having flexible finishing tool can be employed for such type of components. These finishing processes can be classified into two categories: with and without magnetic field assistance. The former includes magnetic abrasive finishing, magnetorheological finishing, and allied processes, and the latter includes abrasive flow finishing. This article reports the critical review of mainly three processes: abrasive flow finishing, magnetorheological finishing, and magnetorheological abrasive flow finishing. In this article, the issues that need attention of the researchers have been categorically mentioned. This article provides a comprehensive literature review of magnetorheological finishing process in terms of rheological characterization of magnetorheological fluid, experimental investigation, theoretical analysis, and applications. This article deals with various advancements in abrasive flow finishing and hybrid processes. The developments in magnetorheological abrasive flow finishing and its allied processes have been discussed in detail. By suitable modification of magnetorheological abrasive flow finishing process, it can achieve surface finish up to nano-meter on different materials such as brass, aluminium, stainless steel, and silicon-nitride.