China 
Africa 
Explore chapters and articles related to this topic
High Entropy Alloys
Published in T.S. Srivatsan, Manoj Gupta, High Entropy Alloys, 2020
P. Neelima, S.V.S. Narayana Murthy, P. Chakravarthy, T.S. Srivatsan
The challenges are often more complex than expected. This is primarily because many of the alloy compositions have to be melted through vacuum induction melting (VIM) to obtain the desired composition, while concurrently controlling the presence of impurities and gases. During VIM, the alloying elements are added either as a virgin material or as a “master” alloy. The sequence of addition of the elements and the time allowed prior to pouring are important parameters, since element loss can often occur even in an inert environment, such as a vacuum, depending on the vapor pressure of the specific element. Elements like cadmium (Cd), zinc (Zn), and manganese (Mn), which have a high vapor pressure are often prone to experience significant loss during melting and immediately prior to pouring. On the other hand, melting can be also be conducted in an environment of argon (Ar) gas pressure to minimize loss of the specific element. To obtain the required composition and to concurrently take in to account an apparent loss of the high vapor pressure elements, an additional amount of the specific elements must be added to compensate for the loss. The parameters that exert an influence on the loss must be studied to provide an estimate of the loss experienced by a specific element for purposes of compensation.
Small-scale deformation behaviour of the AlCoCrFeNi2.1 eutectic high entropy alloy
Published in Philosophical Magazine, 2022
Shailesh Kumar Singh, Govind Kumar, Pokula Narendra Babu, Snehanshu Pal, Saurabh Vashistha, M. S. Azam, Saurabh Dixit
The alloy was prepared by the Vacuum Induction Melting (VIM) route in rectangular ingots. The required weight of pure metals is charged into a VIM furnace having an alumina crucible. The melting was carried out around 1600–1750°C. The temperature was monitored using K-type thermocouple installed in the furnace and the melting process was performed under an argon atmosphere. The electromagnetic stirring action was carried out to achieve homogeneity of the melt. The chemical composition of as-cast material was measured using Inductively Coupled Plasma (ICP) Atomic Emission Spectrometry and reported in Table 1 The chemical composition of the individual phases B2 and L12 were determined using FESEM-EDS and reported in Table 1. The multiple readings of EDS analysis were taken, and the average value was reported. The EDS analysis of the sample exhibit that the material under investigation comprised of five principal elements (i.e. having atomic % greater than 5) and satisfied the criteria of high entropy alloy [26].
Enhanced cold deformability of a marine Cu-Ni-Al–Fe-Mn alloy produced by HCCM vertical continuous casting: effect of deformation mechanism and second phases
Published in Philosophical Magazine, 2022
Fan Zhao, Qiang Lu, Yu Lei, Xinhua Liu
The CuNi6.66Al6.82Fe2.42Mn2.06 (wt%) alloy was prepared by vacuum induction melting. The ingots were remelted and casted to bars with a diameter of 20 mm by HCCM vertical continuous casting equipment that we developed for laboratory investigation, which is schematically shown in Figure 1. The equipment is composed of four parts, which are the crucible melting system, thermal heating system, mould cooling system and traction system. The molten metal flows out of the graphite crucible and into the graphite thermal mould for heat preservation. Then, the metal flows into the graphite casting mould and is solidified by the crystallizer cooling system. The casting bar moves downward by the traction of dummy bar to achieve continuous casting. Through the coordination of forced heating, forced cooling and traction system, a strong temperature gradient is formed at the front edge of the solid–liquid interface. The temperature in crucible, temperature of graphite thermal mould and cooling water flow rate of crystallizer were 1300 ± 5°C, 1250 ± 5°C and 400 L/h, respectively. For comparative studies, the continuous casting speeds were controlled as 0.5, 1.0, 1.5, 2.0 mm/s, and a polished mould casting alloy with the same composition and dimension was also adopted. The casting rods were rolled at the ambient temperature by a two-high rolling mill. The rolling speed was 10 m/min, and the accumulative reduction was 20%, 40%, 60%, 80% and 94%, respectively.
Microstructure and properties of ZrO2-reinforced 24CrNiMoY alloy steel prepared by selective laser melting
Published in Powder Metallurgy, 2018
Qing Xia, Suiyuan Chen, Chaofan Shi, Zhuang Li
In this paper, Q235 steel with a size of 100 mm × 100 mm × 10 mm was used as the substrate. The surface was polished to a roughness of Ra 6.5, and then cleaned with alcohol to improve the surface flatness. 24CrNiMoY alloy steel powder was prepared by the VIGA technology (vacuum induction melting atomisation). The chemical composition of the 24CrNiMoY powder is shown in Table 1. The particle size distribution is shown in Figure 1. It can be seen that the particle size of the alloy steel powder is mostly 1–80 μm, which meets the requirements of the SLM process [2]. The zirconia powder added to 24CrNiMo is micrometre-sized, and the crystal type belongs to amorphous zirconia. 0.5% zirconia powder mixed with 24CrNiMoY alloy steel particle is shown in Figure 2. As can be seen, the 24CrNiMoY powder is spherical, and the amorphous zirconia powder is distributed around the 24CrNiMoY powder.