A nickel-based single-crystal superalloy was employed to investigate the preferred growth orientation behavior of the (γ + γ') eutectic and the effect of these orientations on the segregation behavior. A novel solidification model for the eutectic island was proposed. At the beginning of the eutectic island's crystallization, the core directly formed from the liquid by the eutectic reaction, an...

The mean and the life-limiting behavior under fatigue of the nickel-based superalloy, IN100, separated (or converged) as a function of stress level and dwell loading. This behavior was related to the control of the life-limiting behavior by the smallcrack growth regime, producing its much slower response to stress level and dwell-time, relative to the mean-lifetime behavior. The lifetime probab...

Fatigue tests have been conducted on an advanced disc Ni-based superalloy (Low Solvus, High Refractory (LSHR) alloy) at 650 C in air under three-point bend loading to investigate the role of orientation-dependent grain boundary oxidation in crack initiation and early propagation. It is found that crack initiation occurs mainly from bulged grain boundary oxides, and cracks then predominantly pro...

We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic suscep...

The damaged K465 nickel-based superalloy parts were repaired by laser forming repair technology. The cracking characteristics and grain boundary liquation in heat affected zones were investigated by optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was found that the cracks originated from the heat-affected zone and extended to the repai...

Serial sectioning methods continue to produce a wealth of image data for quantifying the three-dimensional nature of material microstructures. In this work, we discuss a computational methodology for automated detection and 3D characterization of dendrite cores from images taken from slices of a production turbine blade made of a heat-treated single crystal Ni-based superalloy. The dendrite cor...

Fretting experiments were conducted on the (10 0) crystal (cubic) face of a single crystal Ni-base superalloy in two directions, /10 0S and /110S, to study the effect of crystallographic orientation on the fretting response in both partial slip and gross slip regimes. The study involved point contacts using a tungsten carbide (WC) ball with radius 10 mm tested at room temperature. Ball indentat...

The oxidation of both low and high-activity simple and Pt-modified aluminide coatings on nickel base superalloy IN738 has been studied in static air at 1100 OC up to 1000 h. For all coatings oxidation followed a parabolic law up to 400 h. The two Pt-modified coatings showed better protectiveness with lower mass gains and smaller rate constants, especially for long reaction times. The presence o...

Ni-Cr-Mo-based superalloy is widely used as a key component in many critical environments. To ensure that the manufacturing process does not impact long-term service performance of these components, aging precipitation behavior at different temperatures and its effect on intergranular corrosion (IGC) resistance wear C276 were investigated. The equilibrium phase diagram was calculated first usin...

In order to investigate the mechanical properties of developed wrought γ'-hardened Ni-based superalloy, LESS alloy (Low Eta Sigma Superalloy), and understand deformation behavior, tensile tests were carried out from room temperature 800oC in comparison with IN 740H alloy. Like other superalloys, found be dependent on temperature. As rose between 700oC, ultimate strength (UTS) decreased slightly...