Exploring the microstructure manifold: Image texture representations applied to ultrahigh carbon steel microstructures

Rare earth metals are used in semiconductors, solar cells and catalysts. This review focuses on the background of oxide metallurgy technologies, the chemical and physical properties of rare earth (RE) metals, the background of oxide metallurgy, the functions of RE metals in steelmaking, and the influences of RE metals on steel microstructures. Future prospects for RE metal applications in steelmaking are also presented.

Effects of Rare Earth Metals on Steel Microstructures

Laves phases with their comparably simple crystal structure are very common intermetallic phases and can be formed from element combinations all over the periodic table resulting in a huge number of known examples. Even though this type of phases is known for almost 100 years, and although a lot of information on stability, structure, and properties has accumulated especially during the last about 20 years, systematic evaluation and rationalization of this information in particular as a function of the involved elements is often lacking. It is one of the two main goals of this review to summarize the knowledge for some selected respective topics with a certain focus on non-stoichiometric, i.e., non-ideal Laves phases. The second, central goal of the review is to give a systematic overview about the role of Laves phases in all kinds of materials for functional and structural applications. There is a surprisingly broad range of successful utilization of Laves phases in functional applications comprising Laves phases as hydrogen storage material (Hydraloy), as magneto-mechanical sensors and actuators (Terfenol), or for wear- and corrosion-resistant coatings in corrosive atmospheres and at high temperatures (Tribaloy), to name but a few. Regarding structural applications, there is a renewed interest in using Laves phases for creep-strengthening of high-temperature steels and new respective alloy design concepts were developed and successfully tested. Apart from steels, Laves phases also occur in various other kinds of structural materials sometimes effectively improving properties, but often also acting in a detrimental way.

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Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

The effect of microstructure evolution on the mechanical properties of martensite ferritic steel during long-term aging

Study on the nucleation and growth of M23C6 carbides in a 10% Cr martensite ferritic steel after long-term aging

Influence of Rare Earth Elements on Microstructure and Mechanical Properties of Cast High-Speed Steel Rolls

Study on the nucleation and growth of Laves phase in a 10% Cr martensite ferritic steel after long-term aging

The decomposition behavior of martensite and precipitation characteristics of carbonitrides during the tempering process of a low-alloy high-speed steel (semi-HSS) containing nitrogen were investigated by means of transmission electron microscopy, scanning electron microscopy, energy dispersive spectrometry and electron energy loss spectroscopy. The results shown the secondary hardening effect is reinforced with addition of nitrogen and the secondary hardening temperature range has expanded. The stability of retained austenite is also studied. When tempered in the temperature range of 425–525 °C, large quantities of fine-scale V-rich nitride precipitations distribute in the matrix homogeneously. A complex carbonitride phase can form when tempered at 550 °C.

Tempering behavior of a semi-high speed steel containing nitrogen

Evolution and its stability of M23(C,N)6 carbonitride in martensite ferritic steel during long-term thermal aging

The austenite cooling transformation kinetics of a semi-high-speed steel (HSS) with or without additional nitrogen was studied by means of DT1000 dilatometer. The stability and composition of the carbides have also been investigated using transmission electron microscopy and scanning electron microscopy. The results indicate that the addition of nitrogen can improve the hardening ability and bring down the M s temperature of the steel. The carbides in the semi-HSS with nitrogen addition contain more W and Mo elements and less Cr element. They exhibit higher stability. Quenching hardness of the semi-HSS with N is insensitive to the austenization temperature in the range from 1223 to 1423 K.

Yan Wang

Papers

Influence of Rare Earth Elements on Microstructure and Mechanical Properties of Cast High-Speed Steel Rolls

Study on the nucleation and growth of Laves phase in a 10% Cr martensite ferritic steel after long-term aging

Tempering behavior of a semi-high speed steel containing nitrogen

Evolution and its stability of M23(C,N)6 carbonitride in martensite ferritic steel during long-term thermal aging

Effect of nitrogen on the austenite cooling transformation kinetics of a high-speed steel