Springer Science and Business Media LLC

The term “long-term creep properties” for heat resistant steels is mainly reflected by the 100.000 hour creep rupture strength at elevated testing temperature. Often, results of high stress, short-term creep tests are extrapolated to this 100.000 hour target value. Results of long-term creep tests are rather rare because of high testing costs and the time consuming testing procedure. Especially, long-running crossweld creep tests have not been performed in a sufficient extent so far, although, the heat-affected zone of crosswelds of ferritic chromium steels is known as a possible weak point. The long-term creep properties of crosswelds is linked to microstructure of the heat-affected zone of 9–12% chromium steels. The formation of heat-affected zone microstructures is studied by dilatometry, in-situ X-ray diffraction using synchrotron radiation, optical microscopy as well as most advanced electron microscopic methods. Results of crossweld creep tests up to duration of 40,000 hours are directly linked to the heat-affected zone microstructure at the location of fracture. The most predominant failure mechanism at lower stress levels and long term duration is Type IV cracking in the fine-grained heat-affected zone region of crosswelds. The failure mechanism is discussed in detail in this paper.

In this paper, the fretting wear and fretting corrosion behaviour of the AA6063 alloys and hybrid AA6063 matrix composite (HAMCs) was studied. The optical microscope and secondary electron microscope were used to characterize the microstructural features of the HAMCs. The composites were subjected to a dry fretting wear test under three different applied loads (5 N, 10 N, and 15 N). In comparison with the base material, the HAMCs demonstrated a significant increase (3.7 times) in specific wear resistance. The dissipation energy was reduced in HAMCs (15.9 × 10−3 J) as compared to the base material (24.2 × 10−3 J). The coefficient of friction and open-circuit potential decreased in the fretting regime in fretting corrosion as compared to dry fretting wear. The HAMCs exhibited higher fretting corrosion resistance as compared to base materials. The predominant wear mechanism of the fretting corrosion was abrasion, cracks, delamination, and corrosion.

Ever-growing list of chemical contaminants released into the environment through excessive industrialization on a large scale includes numerous chemical pollutants more prominently heavy metals. The discharge of heavy metals in aqueous system and their removal have been a challenging task for environmentalists for last one decade. Keeping these views in mind, the present study highlights the efficacy of shelled Moringa oleifera seeds (SMOS) in decontaminating Cd (II) and Pb (II) ions from aqueous environment both present as single metal and as binary metal solution. The extent of adsorption capacity for Cd (II) and Pb (II) on Moringa oleifera seeds for binary metal ions [76.59% and 81.10%] was found to be low as compared to single metal ions [85.10% and 96.10%]. Morphological changes observed in Scanning Electron Micrographs of native and treated SMOS indicates the existence of biosorption phenomenon. Fourier Transform Infrared Spectrometry of the exhausted seed biomass highlights amino acids-metal interaction responsible for sorption phenomenon. The sorption capacity of regenerated biomass remained almost constant after three cycle of sorption suggesting that the lifetime cycle was sufficient for continuous application.

The present investigation deals with the study and comparison of low cycle fatigue (LCF) behavior of modified IN 718 alloy with higher Al+Ti/Nb and Al/Ti ratios of 0.458 and 0.870, with that of conventional IN 718 alloy with corresponding ratios of 0.294 and 0.50 respectively. LCF tests were carried out in total strain control mode at total strain amplitudes (Δɛt/2) from ±0.625% to ±1.0%, in fully reversed loading (R= −1) at 650°C. The modified alloy was found to exhibit better LCF resistance than the conventional alloy.

The inhibition of corrosion of carbon steel in well water using diethylenetriamine penta (methylene phosphonic acid) (DETPMP), Zinc ions and dodecyltrimethylammonium bromide (DTAB) was investigated using weight-loss measurement, electrochemical polarization and impedance methods. Inhibition efficiency of above ternary inhibitor reaches maximum values at 93 %. The biocidal efficiency of DTAB was studied which reaches maximum of 88 % at 125 ppm DETPMP, 10 ppm Zn2+ and 150 ppm DTAB. The shape of DC polarization profile revealed the new ternary system which acts as anodic type inhibitor. AC impedance spectroscopic studies indicated the formation of a protective film onto the metal surface in the presence of inhibitors. Analyses of the protective film using scanning electron microscope, energy dispersive X-ray analysis, atomic force microscopy and Fourier transfer infrared spectroscopy have revealed that the film consists of Zn(OH)2, oxides and hydroxides of iron and the inhibitor molecules in the form of a complex.

The experimental study of hypoeutectic Al-7.3Si alloy on microstructure and mechanical properties processed by MDF at room temperature was reported in this paper. A commercial LM-25 aluminium alloy ingot was melted in an electric casting furnace and poured into a preheated rectangular casting die. The samples were then solutionized for 10 h at 535 °C and quenched in water for MDF processing. Microstructure analysis of the samples was done with the help of optical microscopy and scanning electron microscopy. Microstructural observation of MDF processed up to six passes sample showed that coarse eutectic silicon particles with an average length of 16 µm are effectively broken into fine particles with an average length of 4 µm and uniformly distributed in aluminium phase. After six passes, UTS of as-cast specimen is increased from 177 to 441 MPa and microhardness is increased from 75 to 127 Hv. XRD analysis of the samples confirmed the presence of Al phase and eutectic Si phase. Therefore, modification of eutectic Si particle with Al phase refinement has been demonstrated to be a very important factor for enhancing mechanical properties of aluminium–silicon alloy.