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This paper explores the effects of solution treatment on hot workability and mechanical properties of a Ni3Al-based alloy named IC-221M. As-cast IC-221M alloy cracked during the hot working process. Optical and scanning electron microscopy revealed that cracks initiated and propagated through ?+Ni5Zr eutectic phase during hot working. This eutectic phase reduced remarkably after the heat treatment at 1100 ◦C for 20 h as revealed by the thermal analysis and SEM micrographs. The 20 h solution treated alloy could be hot worked without cracking even at such high strain rates as 100/s. Also, compressive yield strength of the solution treated alloy at temperatures above 700 ◦C was higher than that of the as-cast alloy

For full-text Email m.hadi@iut.ac.ir The purpose of this study was to investigate the effects of temperature and strain rate on the hot deformation behavior of medium-carbon structural steel. This steel is known as 30XΓCA steel in GOST standard and contains 0.3 wt % carbon. To investigate the hot deformation behavior of this steel, hot compression tests were performed on cylindrical samples in temperature ranges from 800 to 1000°C and strain ranges from 0.001 to 0.1 s–1. The Microstructure of samples was characterized using optical microscopy (OM) and scanning electron microscopy (SEM). The true stress-strain curves of 30XΓCA steel obtained at various deformation conditions showed that the softening phenomenon based on recovery and dynamic recrystallization (DRX) occurred during hot deformation tests. The results indicated that the peak stress decreased with increasing temperature and decreasing strain rate. With increasing temperature from 800 to 1000°C, the peak stress decreased by 52, 60, and 38% at strain rates of 0.001, 0.01 and 0.1 s–1, respectively. According to the results, it can be claimed that the DRX was a dominate mechanism of softening in all deformation conditions. The changes of work hardening rate for 30XΓCA steel during hot deformation were analyzed to confirm the results. Accordingly, it was observed that critical stress for the initiation of DRX decreased with increasing temperature and decreasing strain rate. Furthermore, constitutive equations and activation energy of deformation for 30XΓCA steel were successfully determined. Based on the hyperbolic sine equation, the activation energy of hot deformation of 30XΓCA steel was 256.11 kJ/mol. Hot Deformation Behavior and Constitutive Modelling of a Medium-Carbon Structural Steel | SpringerLink

Commonly, the low wear resistance of stainless steels damages them during usage; in order to enhance wear properties, various types of tungsten-carbide-based coatings, such as WC-Co and WC-Ni, could be applied on the steel surface. To improve the mechanical properties of the coatings, instead of nickel- or cobalt-bearing coatings, WC-FeAl composite coating is used. Following the previous studies on laser cladding of the WC-FeAl composite powder on 321 stainless steel, the mechanical properties and wear characteristics of the coats are discussed here. Mechanical evaluations showed that hardness, fracture toughness, and the modulus of elasticity of the coating were, respectively, 1600 HV, 5.7 MPa m1/2, and 355 GPa. Moreover, a wear test was conducted at ambient temperature with a 30 N load for 3000 m. The results indicated that by applying the coating, the weight loss of the 321 steel decreased from 146 to 0.7 mg. Besides, the wear rate of the coated sample was 0.57 mm3/N m. Further analysis conducted on the worn surfaces of the coated samples depicted that parallel scratches formed on the surface, indicating that the abrasion wear was the main mechanism for WC-FeAl coating https://doi.org/10.2351/7.0000219