scholarly journals The Influence of Holding Time on the Microstructure Evolution of Mg–10Zn–6.8Gd–4Y Alloy during Semi-Solid Isothermal Heat Treatment

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 420 ◽  
Author(s):  
Shuang Nie ◽  
Bingyang Gao ◽  
Xuejian Wang ◽  
Zhiqiang Cao ◽  
Enyu Guo ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Boundaries ◽  
Microstructure Evolution ◽  
Treatment Process ◽  
Ostwald Ripening ◽  
Eutectic Structure ◽  
Holding Time ◽  
Isothermal Heat Treatment ◽  
Heat Treatment Process ◽  
Semi Solid

A semi-solid microstructure of Mg–10Zn–6.8Gd–4Y alloys is acquired via an isothermal heat treatment process, and the effects of the holding time on the microstructure evolution of Mg–10Zn–6.8Gd–4Y alloys are investigated. The results show that the microstructure of the cast alloy is composed of primary α-Mg dendritic grains with a eutectic structure (W-phase and eutectic Mg) distributed at the grain boundaries. The primary α-Mg dendritic grains grow in size with increasing holding time, and they tend to grow into more globular structures in the initial stage; they then become a bit more dendritic, as small branches grow from the grain boundaries after holding the sample at 580 °C for 10 min. Meanwhile, the interdiffusion of magnesium atoms within the eutectic region, and between the primary α-Mg and eutectic structure, leads to the formation of fine and relatively globular eutectic Mg grains in the eutectic structure after holding for 10 min. The eutectic Mg grains begin to grow, coarsen, coalesce, or be swallowed by the surrounding primary grains, causing fluctuations of the general grain size. Over the whole isothermal heat treatment process, two mechanisms—coalescence and Ostwald ripening—dominate the grain coarsening.

Effects of SiC Particle and Holding Time on Semi-Solid Microstructure of SiCP/AZ61 Composites

2010 ◽  
Vol 152-153 ◽  
pp. 628-633
Author(s):  
Fa Yun Zhang ◽  
Jian Xiong Ye ◽  
Hong Yan
Keyword(s):  
Heat Treatment ◽  
Microstructure Evolution ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Isothermal Holding ◽  
Holding Time ◽  
Isothermal Heat Treatment ◽  
Particle Volume ◽  
Semi Solid ◽  
Sic Particle

Effects of SiC particle and holding time on microstructure evolution of SiCP/AZ61 composites during semi-solid isothermal heat treatment method were studied, and evolution mechanism of semi-solid microstructure of composites was discussed. The results indicated that the process of microstructure evolution of SiCP/AZ61 composites by the isothermal holding at the temperatures of 595°C for different times (0min~90min) experienced in succession the rapid merging of the secondary dendritic arms →large massive structure→melting and separating of the local grain boundary →spheroidization of the gains →slowing growth of globular microstructure. Synthetically, after isothermal holding at 595°C for 30min to 60min the favorable semi-solid microstructure can be obtained; Compared with the monolithic AZ61alloy, microstructure of SiCP/AZ61 composites during semi-solid isothermal heat-treatment was finer as a result of entering of Sic particle, and with the increasing of SiC particle volume fraction, globular gain size was smaller.

Effect of Heat Treatment Process on the Preparation of Foamed Glass Ceramic from Red Mud and Fly Ash

2014 ◽  
Vol 670-671 ◽  
pp. 201-204 ◽  
Author(s):  
Yu Xi Guo ◽  
Yi He Zhang ◽  
Hong Wei Huang ◽  
Pan Hu
Keyword(s):  
Heat Treatment ◽  
Fly Ash ◽  
Glass Ceramic ◽  
Red Mud ◽  
Treatment Process ◽  
Sintering Temperature ◽  
Holding Time ◽  
Heat Treatment Process ◽  
Ceramic Foams

Lightweight glass ceramic foams have been prepared from a mixture of solid wastes, namely 40 wt-% red mud and 60 wt-% fly ash. In this work, we illustrate the effects of variables in heat treatment process, including the sintering temperature and the holding time, on the quality of the foams. The reduction of sintering temperature as well as the holding time, was found to limit the coalescence and improve the apparent density and the compressive strength.

Research on the Microstructure and Properties of Hypereutectic Al-Si Alloy for Semi-Solid Forming during Heat Treatment

2014 ◽  
Vol 887-888 ◽  
pp. 349-356
Author(s):  
Xiang Fan ◽  
Yi Tao Yang
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Solution Temperature ◽  
Heat Treatment Process ◽  
Aluminum Silicon Alloy ◽  
Liquid Line ◽  
And Performance ◽  
Semi Solid ◽  
Change Of Microstructure ◽  
Microstructure And Performance

The heat treatment process of a kind of hypereutectic aluminum silicon alloy which is suitable for semi-solid forming and the change of microstructure and performance during the process of heat treatment had been studied in this paper. In order to guide the heat treatment process, the phase diagram of the alloy had been calculated by the software of Thermo-Calc, and the theoretical solid and liquid line had been gotten. Twelve kinds of heat treatment process had been selected in this study. Finally the best process which the solution temperature is 495°C for 2h and aging temperature is 160°C for 8h had been gotten.

Microstructure Evolution of TiB2/7075 Composites in Semi-Solid State near Liquids within Holding Time

2019 ◽  
Vol 285 ◽  
pp. 127-132
Author(s):  
Gui Sheng Gan ◽  
Da Quan Xia ◽  
Xin Liu ◽  
Cong Liu ◽  
Han Lin Cheng ◽  
...  
Keyword(s):  
Solid State ◽  
Microstructure Evolution ◽  
Ostwald Ripening ◽  
Holding Time ◽  
Al Alloy ◽  
Matrix Composites ◽  
Semi Solid ◽  
Al Matrix Composites ◽  
Settling Process ◽  
Al Matrix

Novel reactive technique has been employed in synthesis of 7075 Al matrix composites, and effect of TiB2 particles on sedimentation and microstructure of 7075 Al Alloy in near liquidus was investigated. Researchers have shown that 4.5%TiB2/7075 composites had the smallest grains and the minimum liquidus and solidus temperatures in 7075 Al matrix composites. 4.5%TiB2/7075 composites holding for 21 hours appeared stratification phenomenon, the globular grains were 61μm and 214μm, 250μm and 283μm with the increase of holding time respectively. The microstructures evolution of TiB2 /7075 composites holding for different time at 635°C was a two-stage mechanism that the globular grains was formed firstly and secondly sedimentation and layering were began after a period of time of Ostwald ripening. The globular grain continued to increase during the settling process.

Surface Modification of 2205 Duplex Stainless Steel by Low Temperature Thermochemical Hybrid Heat Treatment at 450° C

2013 ◽  
Vol 845 ◽  
pp. 408-411
Author(s):  
M.S. Adenan ◽  
M.N. Berhan ◽  
E. Haruman
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Low Temperature ◽  
Duplex Stainless Steel ◽  
Treatment Process ◽  
Surface Hardness ◽  
Horizontal Tube ◽  
Holding Time ◽  
Hardness Profile ◽  
Heat Treatment Process

An approach has been made in developing hybrid heat treatment process for improvement of surface properties of duplex stainless steel (DSS). The process was performed using horizontal tube furnace at temperature of 450° C at holding time of 4, 8, 16 and 30 hours. Carbon and nitrogen elements were simultaneously introduced onto the surface of DSS with a ratio of 5% CH4 + 25% NH3 + 70% N2. The microstructure, phase analysis, surface hardness and hardness profile were systematically assessed. Hybrid heat treatment process managed to produce diffusional layer, where longer holding time had increased the thickness of the layer and improved the surface hardness. Expanded austenite phase has been formed at specimens 8, 16 and 30 hours. Longer holding time however gradually diffused Cr2N at the ferrite grains at the substrates. From the process, it can be concluded that low temperature hybrid heat treatment be able to improve the surface hardness of DSS however concern on holding time must be highly considered.

scholarly journals Effect of Holding Time and Cooling Media on Heat Treatment Process to Gear Motor Indopart Hardness

2021 ◽  
Vol 1125 (1) ◽  
pp. 012116
Author(s):  
Klemens A. Rahangmetan ◽  
Cipto ◽  
Christian W. Wullur ◽  
D Parenden ◽  
Farid Sariman
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Holding Time ◽  
Heat Treatment Process ◽  
Cooling Media
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