Microstructure of semi-solid ADC12 aluminum alloy adopting new SIMA method

2010 ◽  
Vol 20 ◽  
pp. s744-s748 ◽  
Author(s):  
Zhen-yu WANG ◽  
Ze-sheng JI ◽  
Li-xin SUN ◽  
Hong-yu XU
Keyword(s):  
2021 ◽  
pp. 130756
Author(s):  
Yan Liu ◽  
Xiaolin Chen ◽  
Minqiang Gao ◽  
Renguo Guan

2008 ◽  
Vol 141-143 ◽  
pp. 163-168 ◽  
Author(s):  
Xiang Jie Yang ◽  
Hong Min Guo

Rheo-die casting (RDC) based on LSPSF (low superheat pouring with a shear field) rheocasting process has been exploited. In case of secondary die casting aluminum alloy YL112, LSPSF allowed for preparation of sound semi-solid slurry in 15-20s that fully meet the production rate of HPDC, the primary α-Al exhibiting a mean equivalent diameter of 70 μm and shape factor of 0.93, without any entrapped eutectic. Compared to conventional HPDC, RDC improves microstructures in castings. Secondary solidification of semi-solid slurry takes place uniformly throughout the entire cavity, producing an extremely fine and uniform microstructure. The experimental results show the RDC 380 alloy has much improved integrity and mechanical properties, particularly elongation, and heat treatment can be used to enhance the mechanical properties.


2022 ◽  
Vol 327 ◽  
pp. 263-271
Author(s):  
Gan Li ◽  
Jin Kang Peng ◽  
En Jie Dong ◽  
Juan Chen ◽  
Hong Xing Lu ◽  
...  

There is a strong demand for high-strength aluminum alloys such as 7075 aluminum alloy to be applied for rheocasting industry. The overriding challenge for the application of 7075 alloy is that its solid fraction is very sensitive to the variation of temperature in the range of 40% ~ 50% solid fraction, which inevitably narrows down the processing window of slurry preparation for rheocasting process. Therefore, in this work, a novel method to prepare semi-solid slurry of the 7075 alloy, so called Enthalpy Control Process (ECP), has been developed to grapple with this issue. In the method, a medium-frequency electromagnetic field was applied on the outside of slurry preparation crucible to reduce the temperature difference throughout the slurry. The effect of processing parameters, including heating power, heating time, the initial temperature of crucible and melt weight, on the temperature field of the semi-solid slurry was investigated. The results exhibited that although the all the processing parameters had a great influence on the average temperature of the slurry, heating time was the main factor affecting the maximum temperature difference of the slurry. The optimum processing parameters during ECP were found to be heating power of 7.5 KW, the initial temperature of crucible of 30 °C ~ 200 °C and melt weight of 2 kg.


Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 637 ◽  
Author(s):  
Chaiyoot Meengam ◽  
Yongyuth Dunyakul ◽  
Dech Maunkhaw ◽  
Suppachai Chainarong

Transient Liquid Phase Bonding (TLPB) process of semi-solid metal 7075 aluminum alloys (SSM7075) using 50 μm thick of ZA27 zinc alloys as interlayers for the experiment were carried out under bonding temperatures of 480 and 540 °C and bonding times of 30, 60, 90 and 120 min respectively. In the bonding zone, the semi-solid state of ZA27 zinc alloy interlayers were diffused into the SSM7075 aluminum alloy. Examination of the bonding zone using Scanning Electron Microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDS) showed that the precipitation of the intermetallic compound of η(Zn–Al–Cu), β(Al2Mg3Zn3), T′(Zn10Al35Cu55) and MgZn2 were formed in the bonding zone. The better homogenized microstructure in the bonding zone was formed when increasing bonding time and bonding temperature. The highest bonding strength was recorded at 17.44 MPa and average hardness was at 87.67 HV with the bonding time of 120 min and temperature at 540 °C. Statistically, the coefficient of determination analysis of bonding strength data was at 99.1%.


2016 ◽  
Vol 256 ◽  
pp. 294-300 ◽  
Author(s):  
Jin Long Fu ◽  
Yu Wei Wang ◽  
Kai Kun Wang ◽  
Xiao Wei Li

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.


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