JOM

Structural performance of magnesium alloys depends strongly on specific deformation mechanisms operating during mechanical loading. Therefore, in situ monitoring of the acting mechanisms is a key to performance tailoring. We review the capacity of the advanced acoustic emission (AE) technique to understand the interplay between two primary deformation mechanisms—dislocation slip and twinning—in real time scale. Details of relative contributions of dislocation slip and deformation twinning to the mechanical response of pure Mg and Mg-Al alloy are discussed in view of AE results obtained with the aid of recently proposed spectral and signal categorization algorithms in conjunction with with neutron diffraction data.

Rapid solidification plasma deposition (RSPD) is a unique process for producing metallurgical structures. Homogeneous, nearly fully dense microstructures are achieved which have significantly improved mechanical behavior relative to the behavior of the same alloys in conventionally cast and heat-treated form, such as a 50% increase in tensile strength and a many-fold increase in thermal fatigue crack initiation resistance. Thin-walled structures can be produced in alloys which could not be cast or wrought to that size, while massive fine-grained structures can be produced in a fraction of the time of conventional processes.

Red mud based ceramic tiles were successfully fabricated by high-temperature sintering and the influence of the Fe2O3 content on their comprehensive performance, mineral phase, and microstructure were systematically investigated. The results indicate that iron is involved in the structural reorganization of mullite during the nucleating process. Adding 9% Fe2O3 elongated mullite crystals to an aspect ratio of 15.6 ± 2.1, and the crystals were successfully obtained at a sintering temperature of 1300°C for 2 h. In this case, the values for water absorption and compressive strength of the red mud based ceramics were 6.6% and 178.3 MPa, respectively, reaching the national standard for building materials. Putting the right amount of Fe2O3 into ceramics can not only promote the anisotropic growth of mullite crystals but can result in the formation of an interlocked network of mullite at lower temperatures. This work will contribute to a better understanding of the influence of Fe2O3 on basic material performance, such as structural, micro-analysis, and mechanical characteristics of ceramic tiles with iron-containing mullites.