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

Precipitate coarsening and its effects on the hot deformation behavior of the recently developed γ'-strengthened superalloys

High-performance conventional engineering materials (including Al alloys, Mg alloys, Cu alloys, stainless steels, Ni superalloys, etc.) and newly-developed high entropy alloys are all compositionally-complex alloys (CCAs). In these CCA systems, the second-phase particles are generally precipitated in their solid-solution matrix, in which the precipitates are diverse and can result in different strengthening effects. The present work aims at generalizing the precipitation behavior and precipitation strengthening in CCAs comprehensively. First of all, the morphology evolution of second-phase particles and precipitation strengthening mechanisms are introduced. Then, the precipitation behaviors in diverse CCA systems are illustrated, especially the coherent precipitation. The relationship between the particle morphology and strengthening effectiveness is discussed. It is addressed that the challenge in the future is to design the stable coherent microstructure in different solid-solution matrices, which will be the most effective approach for the enhancement of alloy strength.

https://www.mdpi.com/1099-4300/20/11/878/pdf

Coherent Precipitation and Strengthening in Compositionally Complex Alloys: A Review

Coarsening behavior of γ′ precipitates in the γ'+γ area of a Ni3Al-based alloy

Refinement mechanism of cerium addition on solidification structure and sigma phase of super austenitic stainless steel S32654

Precipitation and hot deformation behavior of austenitic heat-resistant steels: A review

This study aims to explore the effect of pathogenesis-based individualised thrombectomy on the clinical results and prognoses of acute intracranial large-artery occlusion.A total of 151 patients were included in this prospective study and divided into the control group (stent thrombectomy, 53 cases), a direct aspiration first pass technique (ADAPT) group (52 cases) and the stent group (stent thrombectomy or a combination of stent thrombectomy and ADAPT, 46 cases) based on whether stent or ADAPT was used. We compared and analysed the patients' general information, the National Institutes of Health Stroke Scale (NHISS) score at admission, the time between the end of arteriography and revascularisation, the number of thrombectomies, the modified Rankin scale (mRS) score at three months and complications in the three groups.Compared with the control group, the time between the end of arteriography and revascularisation in the ADAPT group was significantly reduced (P 0.05), and the patency rate after one thrombectomy significantly increased (P 0.05). The positive prognosis rate was significantly increased in the stent and ADAPT groups compared with the control group (P 0.05).The application of the ADAPT technique in patients with embolism-induced cerebral infarction can reduce the time of revascularisation. The use of stents in patients with atherosclerosis-induced cerebral infarction can increase the patency rate after one thrombectomy. 

https://www.researchsquare.com/article/rs-148345/latest.pdf

Liu Yongchang

Papers

Precipitation and hot deformation behavior of austenitic heat-resistant steels: A review

Effect of pathogenesis-based individualized thrombectomy on treatment result and prognosis of acute intracranial large-artery occlusion patients