Lattice Misfit between Inclusion and Acicular Ferrite in Weld Metal of Low Carbon Low Alloy Steel
To clarify the mechanism of acicular ferrite formation in low carbon submerged arc weld metals of a Ti-B system with different aluminum contents, the lattice misfit between inclusion and acicular ferrite was investigated. The inclusions were directly sliced into thin foils by a focused ion beam device and crystallographic analyses were performed using a transmission electron microscope. These inclusions were surrounded by a narrow Ti-enriched layer which was identified as TiO. Our results showed that the Baker-Nutting orientation relationship was satisfied between the narrow TiO on the inclusion surface and acicular ferrite.
Microstructural evolution in low carbon steel Ti–B weld metals with several Al levels
Microstructure development in welding material containing Ti and B has been in situ observed by using laser scanning confocal microscopy, with various cooling rates. The samples with different aluminum contents were prepared for the observation. In the sample with low Al/O ratio (0.48–0.73), an acicular ferrite microstructure transforming from intragranular nucleation site was in situ observed. On the other hand, with high Al/O ratio, the bainite microstructure originating from grain boundary of austenite was in situ observed. The transformation temperature decreased with increasing aluminum content. It was clear that the microstructure difference was due to the different inclusion in the matrix. Based on those observations, the chemical composition, cooling rate and microstructure were systematically related and the microstructural developments were summarized as a CCT diagram.
Wood Microbiology: Decay and Its Prevention
Introductory text on the principles of decay and discoloration processes in wood, with emphasis on the major fungal damages which may develop during the growth, storage, and use of wood. The characteristics, detection, effects, and control of microbial attacks are stressed. Provides a synthesis of the current literature on wood microbiology, a rapidly expanding field of study. (Abstractor's note: This is an important resource for conservation researchers studying the decay of wood in art and architecture.) The following is a list of chapter headings: 1) Introduction to wood microbiology; 2) Wood deterioration agents; 3) Characteristics and classification of fungi and bacteria; 4) Factors affecting the growth and survival of fungi in wood (fungal ecology); 5) Fungal metabolism in relation to wood decay; 6) The decay setting: some structural, chemical, and moisture features of wood in relation to decay development; 7) General features, recognition, and anatomical aspects of wood decay; 8) Chemical changes in wood caused by decay fungi; 9) Ultrastructural features of wood decay; 10) Changes caused by decay fungi in the strength and physical properties of wood; 11) Colonization and microbial interactions in wood decay; 12) Decays originating in the stems of living trees; 13) Biodeterioration of stored wood and its control; 14) Wood stains and discolorations; 15) Decay problems associated with some major uses of wood products; 16) Detection of internal decay; 17) Paint mildew and related degradative problems; 18) Natural decay resistance (wood durability); 19) Chemical protection of wood (wood preservation); and 20) Some trends in wood microbiology research and a new emphasis (biotechnology). -- AATA