Applied Numerical Analysis. By C.F. Gerald. Pp. xii, 340. £3·60. 1970. (Addison-Wesley.)

Handbook of SiC properties for fuel performance modeling

Considerable work has been performed on NiAl over the last three decades, with an extremely rapid growth in research on this intermetallic occurring in the last few years due to recent interest in this material for electronic and high temperature structural applications. However, many physical properties and the controlling fracture and deformation mechanisms over certain temperature regimes are still in question. Part of this problem lies in the incomplete characterization of many of the alloys previously investigated. Fragmentary data on processing conditions, chemistry, microstructure and the apparent difficulty in accurately measuring composition has made direct comparison between individual studies sometimes tenuous. Therefore, the purpose of this review is to summarize all available mechanical and pertinent physical properties on NiAl, stressing the most recent investigations, in an attempt to understand the behavior of NiAl and its alloys over a broad temperature range.

Physical and mechanical properties of the B2 compound NiAl

Fe3Al-based iron aluminides have been of interest for many years because of their excellent oxidation and sulfidation resistance. However, limited room temperature ductility (<5%) and a sharp drop in strength above 600 °C have limited their consideration for use as structural materials. Recent improvements in tensile properties, especially improvements in ductility produced through control of composition and microstructure, and advances in the understanding of environmental embrittlement in intermetallics, including iron aluminides, have resulted in renewed interest in this system for structural applications. The purpose of this paper is to summarize recent developments concerning Fe3Al-based aluminides, including alloy development efforts and environmental embrittlement studies. This report will concentrate on literature published since about 1980, and will review studies of fabrication, mechanical properties, and corrosion resistance that have been conducted since that time.

A review of recent developments in Fe3Al-based alloys

With the increasing requirements for microelectromechanical systems (MEMS) regarding stability, miniaturization and integration, novel materials such as wide band gap semiconductors are attracting more attention. Polycrystalline SiC has first been implemented into Si micromachining techniques, mainly as etch stop and protective layers. However, the outstanding properties of wide band gap semiconductors offer many more possibilities for the implementation of new functionalities. Now, a variety of technologies for SiC and group III nitrides exist to fabricate fully wide band gap semiconductor based MEMS. In this paper we first review the basic technology (deposition and etching) for group III nitrides and SiC with a special focus on the fabrication of three-dimensional microstructures relevant for MEMS. The basic operation principle for MEMS with wide band gap semiconductors is described. Finally, the first applications of SiC based MEMS are demonstrated, and innovative MEMS and NEMS devices are reviewed.

http://iopscience.iop.org/article/10.1088/0022-3727/40/20/S19/pdf

Group III nitride and SiC based MEMS and NEMS: materials properties, technology and applications

Rapidly solidified strips of Fe66.5-A128.5-Cr5 alloy with the addition of 0.5wt.% TiB 2 , were produced by planar flow strip casting. Correlations of the microstructure and room temperature mechanical properties were made for strips in the as-cast condition and after annealing at 1273K for periods up to 4hrs. The results showed that grain size, tensile strength, ductility, hardness and Young's modulus were very stable for the times investigated. Studies of tensile fracture surfaces revealed essentially 100% transgranular cleavage in the ascast strip with a greater tendency for intergranular failure after prolonged exposure to high temperatures. TEM studies of this alloy revealed diffraction patterns characteristic of DO 3 ordering but the dislocations observed in both ascast and deformed specimens were those typical of the B2 structure without any extended APBs. This is attributed to the very fine DO 3 , domain size . At room temperature slip is predominant.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S194642740052956X

Alan Wolfenden

Papers

Structure/Property Relationships in a Rapidly Solidified and Annealed Ternary Iron Aluminide