Influence of martensite morphology on the work-hardening behavior of high strength ferrite–martensite dual-phase steel

This study concerns influence of martensite morphology on the work-hardening behavior of high-strength ferrite–martensite dual-phase (DP) steel. A low-carbon microalloyed steel was subjected to intermediate quenching (IQ), step quenching (SQ), and intercritical annealing (IA) to develop different martensite morphologies, i.e., fine and fibrous, blocky and banded, and island types, respectively. Analyses of work-hardening behavior of the DP microstructures by differential Crussard–Jaoul technique have demonstrated three stages of work-hardening for IQ and IA samples, whereas the SQ sample revealed only two stages. Similar analyses by modified Crussard–Jaoul technique showed only two stages of work-hardening for all the samples. Among different treatments, IQ route has yielded the best combination of strength and ductility due to its superior work-hardening behavior. The influence of martensite morphology on nucleation and growth of microvoids/microcracks has been correlated with the observed tensile ductility.     

Mechanical and tribological behavior of alumina and alumina‐CNT reinforced hybrid unsaturated polyester composites

Micro‐ and nano‐scale wear behavior of alumina vis‐á‐vis alumina‐carbon nanotube‐reinforced hybrid composites has been studied. In comparison to the pristine alumina, the alumina‐carbon nanotube hybrid reinforcement resulted in reduced scratch depth and lower frictional coefficient. Addition of carbon nanotube has effectively modified the pristine alumina into a superior wear resistant filler. POLYM. COMPOS., 37:1577–1586, 2016. © 2014 Society of Plastics Engineers     

Bulk and nano‐mechanical behavior of silver and silver‐CNT‐reinforced hybrid polymer composites

The present study concerns study of the Bulk and nano‐mechanical properties of Ag‐CNT vis‐à‐vis Ag reinforced polymer composites. The Ag‐CNT hybrid powder blend was prepared by mechanical milling. Variation of the bulk and nano‐mechanical properties has been attributed to the morphological features and the degree of dispersion of the fillers. It has been found that dispersion of Ag‐CNT hybrid particle is beneficial for improvement of both the mechanical properties. POLYM. COMPOS., 37:2581–2587, 2016. © 2015 Society of Plastics Engineers     

Indentation and scratch behavior of functionalized MWCNT–PMMA composites at the micro/nanoscale

Polymethylmethacrylate (PMMA) and functionalized multiwalled carbon nanotube (F‐MWCNT) based composite films were prepared using solution casting method. Nanoindentation and scratch measurements were carried out to study the influence of F‐MWCNT as the reinforcement on the mechanical properties of the composite at the sub‐micron scale. The composites were prepared with varying weight percentages of F‐MWCNT in the PMMA matrix. The composites containing an adequate amount (0.25 wt%) of F‐MWCNT was found to demonstrate the maximum nanomechanical properties, viz. hardness, elastic modulus, recovery index. Scratch resistance measured in terms of coefficient of friction, also showed maximum value for the PMMA composite reinforced with 0.25 wt% of F‐MWCNT. POLYM. COMPOS., 35:948–955, 2014. © 2013 Society of Plastics Engineers     

Phase Evolution and Mechanical Behavior of 0.36 wt% C High Strength TRIP‐Assisted Steel

Phase evolution in a 0.36 wt% C steel has been studied by thermodynamic calculation and dilatometric analysis with an aim to achieve high strength TRIP‐assisted steel with bainitic microstructure. The equilibrium phase fraction calculated as the function of temperature indicated the formation of δ‐ferrite (≈98%) at 1417°C. In contrast, similar calculation under para‐equilibrium condition exhibited transformation of δ‐ferrite to austenite at the temperature below 1300°C. During further cooling two‐phase (α+γ) microstructure has been found to be stable at the intercritical temperature range. The experimentally determined CCT diagram has revealed that adequate hardenability is achievable in the steel under continuous cooling condition at cooling rate >5°C s^?1. In view of the aforesaid results, the steel has been hot rolled and subjected to different process schedule conducive to the evolution of bainitic microstructure. The hot rolled steel has exhibited reasonably good tensile properties. However, cold deformation of the hot rolled sample followed by intercritical annealing and subsequent isothermal bainitic transformation has resulted in high strength (>1000 MPa) with attractive elongation due to the favorable work hardening condition during plastic deformation offered by the multiphase microstructure.     

Protective Effects of Black Cumin (Nigella sativa) and Its Bioactive Constituent,Thymoquinone against Kidney Injury: An Aspect on Pharmacological Insights

The prevalence of chronic kidney disease (CKD) is increasing worldwide, and a close association between acute kidney injury (AKI) and CKD has recently been identified. Black cumin (Nigella sativa) has been shown to be effective in treating various kidney diseases. Accumulating evidence shows that black cumin and its vital compound, thymoquinone (TQ), can protect against kidney injury caused by various xenobiotics, namely chemotherapeutic agents, heavy metals, pesticides, and other environmental chemicals. Black cumin can also protect the kidneys from ischemic shock. The mechanisms underlying the kidney protective potential of black cumin and TQ include antioxidation, anti-inflammation, anti-apoptosis, and antifibrosis which are manifested in their regulatory role in the antioxidant defense system, NF-κB signaling, caspase pathways, and TGF-β signaling. In clinical trials, black seed oil was shown to normalize blood and urine parameters and improve disease outcomes in advanced CKD patients. While black cumin and its products have shown promising kidney protective effects, information on nanoparticle-guided targeted delivery into kidney is still lacking. Moreover, the clinical evidence on this natural product is not sufficient to recommend it to CKD patients. This review provides insightful information on the pharmacological benefits of black cumin and TQ against kidney damage.     

Quantification of Shear Strain Development in the Through-Thickness Direction During Sliding Wear

Metallurgical and Materials Transactions A - Quantifying strain in a deformation mechanism like wear can be critical to enhancing knowledge on structure–property correlation, especially for...