Effect of isothermal process parameters on semi-solid microstructure of chip-based Al–Cu–Mn–Ti alloy prepared by SIMA method

2020 ◽  
Vol 34 (33) ◽  
pp. 2050385
Author(s):  
Ye Wang ◽  
Maoliang Hu ◽  
Hongyu Xu ◽  
Zesheng Ji ◽  
Xuefeng Wen ◽  
...  
Keyword(s):  
Process Parameters ◽  
Ostwald Ripening ◽  
Isothermal Holding ◽  
Treatment Temperature ◽  
Holding Time ◽  
Isothermal Treatment ◽  
Isothermal Process ◽  
Semi Solid ◽  
Average Size ◽  
Relationship Of

A typical Al–Cu–Mn–Ti aluminum alloy chip was adopted to prepare semi-solid billets by a Strain-Induced Melt Activation (SIMA) method, and the effects of isothermal process parameters on the semi-solid microstructure evolution of the alloy were investigated in this work. The result showed that semi-solid billets with highly spheroidal and homogeneous fine grains could be prepared from chips by the SIMA method. With the increase of isothermal temperature, the finer and near-spherical grains are obtained, the grains coarsen and became ellipse at 903 K because of the coarsening mechanisms of coalescence and Ostwald ripening. The relationship of isothermal holding time and grains size followed the LSW theory well, and more spherical microstructure can be brought by prolonging the holding time until 3000 s. Thus, the optimal isothermal treatment temperature is 893 K and holding time is 3000 s, the corresponding average size and roundness of grains are 137 [Formula: see text]m and 1.108, respectively.

Microstructural Evolution of ZL104 Aluminum Alloy Semi-Solid Billet Fabricated by RAP Process

2019 ◽  
Vol 285 ◽  
pp. 234-239
Author(s):  
Yong Fei Wang ◽  
Sheng Dun Zhao ◽  
Chao Chen ◽  
Peng Dong ◽  
Peng Zhang
Keyword(s):  
Aluminum Alloy ◽  
Ostwald Ripening ◽  
Isothermal Holding ◽  
Isothermal Treatment ◽  
Liquid Droplets ◽  
Microstructural Coarsening ◽  
Average Grain Size ◽  
Cold Rolled ◽  
Semi Solid ◽  
Holding Temperature

In this study, ZL104 aluminum alloy supplied in cold rolled state was introduced in recrystallization and partial melting (RAP) process to fabricate semi-solid billets. During the RAP process, samples cut from cold rolled ZL104 aluminum plate were heated to different semi-solid temperatures, and the effects of isothermal treatment parameters on the microstructures of semi-solid billets were investigated. Results showed that, with the increase of isothermal holding temperature and time, both the average grain size and the shape factor were increased. Namely, the shape of solid grain was more and more spherical, but the size of solid grain was larger and larger, which may be not suitable for semi-solid forming. The size of liquid droplets was increased while the number of liquid droplets was decreased with increasing the isothermal holding temperature and time. Microstructural coarsening of solid grain were attributed to coalescence and Ostwald ripening mechanisms, however, the latter one played a more and more important role with the increase of isothermal holding time and temperature. Additionally, The optimal isothermal holding temperature and time are 570 °C and 5 min, respectively, and the coarsening rate constant is 1357.2 μm3/s at 570 °C.

Microstructure Evolution and Coarsening Mechanism of 7075 Semi-Solid Aluminum Alloy Pre-Deformed by ECAP Method

2016 ◽  
Vol 256 ◽  
pp. 294-300 ◽  
Author(s):  
Jin Long Fu ◽  
Yu Wei Wang ◽  
Kai Kun Wang ◽  
Xiao Wei Li
Keyword(s):  
Aluminum Alloy ◽  
Solid State ◽  
Ostwald Ripening ◽  
Liquid Fraction ◽  
Isothermal Holding ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Semi Solid ◽  
Equiaxed Grains ◽  
Kinetics Of

To investigate the influence of refined grains on the microstructure of 7075 aluminum alloy in semi-solid state, a new strain induced melting activation (SIMA) method was put forward containing two main stages: pre-deformation with equal channel angular pressing (ECAP) method and isothermally holding in the semi-solid temperature range. The breaking up and growth mechanisms of the grains and kinetics of equiaxed grains coarsening during the semi-solid holding were investigated. The results showed that the average grain size after ECAP extrusion decreased significantly, e.g., microstructure with average globular diameter less than 5μm was achieved after four-pass ECAP extrusion. Obvious grain coarsening had been found during isothermal holding in the semi-solid state and the roundness of the grains increased with the increasing holding time. The proper microstructure of 66.8μm in diameter and 1.22 in shape factor was obtained under proper soaking condition (at 590°C for 15 min). Two coarsening mechanisms, namely, coalescence in lower liquid fraction and Ostwald ripening in higher liquid fraction contributed to the grain growth process.

Microstructure of Semi-Solid Extruded Copper Alloy after Heat Treatment

2019 ◽  
Vol 285 ◽  
pp. 146-152
Author(s):  
Nai Yong Li ◽  
Han Xiao ◽  
Chi Xiong ◽  
De Hong Lu ◽  
Rong Feng Zhou
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Copper Alloy ◽  
Treatment Time ◽  
Solid Phase ◽  
Treatment Temperature ◽  
Primary Phase ◽  
Holding Time ◽  
Average Grain Size ◽  
Semi Solid

The semi-solid extruded ZCuSn10P1 copper alloy were annealed at different temperatures and time. The influences of heat treatment temperature and holding time on the microstructure of semi-solid ZCuSn10P1 copper alloy were investigated. The results show that with the increase of heat treatment temperature, the morphology of the semi-solid microstructure was improved, the sharp angle around the primary phase α-Cu and the liquid droplets were reduced. With the increase of heat treatment time, the solid-liquid segregation of the semi-solid structure was improved. The average grain size of the solid phase increased with the increasing of the holding time. After heat treatment, the solid solubility of the primary phase α-Cu increased, and the Sn and P elements in the liquid phase continued to diffuse to the primary phase α-Cu. The microstructure of semi-solid copper alloy was the most uniform after heat treatment at 350°C for 120 min.

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.

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.

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.

Effects of semi-solid isothermal process parameters on microstructure of Mg-Gd alloy

2010 ◽  
Vol 20 ◽  
pp. s402-s406 ◽  
Author(s):  
Gui-hua SU ◽  
Zhan-yi CAO ◽  
Yong-bing LIU ◽  
Yu-hui WANG ◽  
Liang ZHANG ◽  
...  
Keyword(s):  
Process Parameters ◽  
Isothermal Process ◽  
Semi Solid

Remelting Technology and Microstructural Evolution of Semi-Solid Al-7Si-2RE Alloy

2010 ◽  
Vol 33 ◽  
pp. 1-5
Author(s):  
Shi Kun Xie ◽  
Rong Xi Yi ◽  
Xiu Yan Guo ◽  
Xiao Liang Pan ◽  
Xiao Qiu Zheng
Keyword(s):  
Aluminum Alloy ◽  
Microstructural Evolution ◽  
Temperature Control ◽  
Liquid Fraction ◽  
Isothermal Holding ◽  
Control Program ◽  
Holding Time ◽  
Α Phase ◽  
Semi Solid ◽  
Equiaxed Grains

In semi-solid remelting process, the various stages of reheating temperature and isothermal holding time must be accurately controlled in order to obtain the uniformly distributed and small equiaxed grains microstructure. In this paper, a temperature control program was developed and the remelting process for Al-7Si-2RE aluminum alloy was carried out. The results showed that with the raise of reheating temperature and the extension of isothermal holding time, the liquid fraction increases, α-phase grain grows and becomes rounding in the process of Al-7Si-2RE alloy semi-solid remelting. The most reasonable process parameter of reheating temperature is at 585~590°C and its appropriate isothermal holding time are about 10~15min for the semi-solid Al-7Si-2RE alloy.

Effects of Isothermal Process Parameters on the Microstructure of Semisolid Alsi7mg Alloy Produced by EPM

2010 ◽  
Vol 136 ◽  
pp. 202-206
Author(s):  
Wen Tong Tian ◽  
Guang An Zhang
Keyword(s):  
Process Parameters ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Solid Particles ◽  
Isothermal Treatment ◽  
Analysis Software ◽  
Optimal Process ◽  
Isothermal Process ◽  
Isothermal Temperature ◽  
Partial Remelting

The effects of isothermal process parameters on the microstructure evolution of semisolid AlSi7Mg alloy produced by electro-pulse modification(EPM) and partial remelting process were investigated using an image analysis software based on quantitative metallography. The results showed that long isothermal time could make the semisolid particles more globular, but the size of the particles would grow larger; high semisolid isothermal temperature would reduce the solid volume fraction and accelerate the spherical evolution of the solid particles. It was found that the optimal process parameters should be 590°C and 10-20min of isothermal temperature and time respectively based on the conditions of this paper. The mechanism of the particles’ formation was also discussed during the isothermal treatment.

Microstructural Evolution of SiCp/AZ61 Composites during Partial Remelting

2008 ◽  
Vol 141-143 ◽  
pp. 545-549 ◽  
Author(s):  
Hong Yan ◽  
Fa Yun Zhang ◽  
Wei Pan
Keyword(s):  
Microstructural Evolution ◽  
High Stability ◽  
Isothermal Holding ◽  
Holding Time ◽  
Technological Parameters ◽  
Partial Remelting ◽  
Initial Stage ◽  
Semi Solid

The microstructural evolution of SiCp/AZ61 composites during partial remelting was investigated. The results indicated that the suitable technological parameters of SiCp/AZ61 composites were the reheating temperature of 595°C ~ 600°C and isothermal holding time of 30min ~ 60min. The separation of microstructure of AZ61 matrix was faster than that of SiCp/AZ61 composites during the initial stage. In the meantime, SiCp/AZ61composites hold high stability during remelting process and a fine semi-solid thixoforming microstructure can be obtained with increases in temperature and holding time. In addition, the samples of SiCp/AZ61composites were susceptible to serious deformation and running out above 610°C.

Sign in / Sign up

Export Citation Format

Share Document