Influence of Rare Earth Additions on the Microstructure and Mechanical Properties of Al7Si0.3Mg Alloys Processed by Semi-Solid Die Casting and Gravity Die Casting

2019 ◽  
Vol 285 ◽  
pp. 69-74 ◽  
Author(s):  
Long Fei Li ◽  
Da Quan Li ◽  
Min Luo ◽  
Yong Zhong Zhang ◽  
Yong Lin Kang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Grain Boundaries ◽  
Die Casting ◽  
Eutectic Phase ◽  
Microstructure And Mechanical Properties ◽  
Die Cast ◽  
Rare Earth Additions ◽  
Semi Solid

Microstructures with fine globular grains and refined eutectic structures are important to enhance the mechanical properties of A356 alloys processed by semi-solid and gravity die casting. Rare earth (RE) additions have been shown to be capable of refining both the α-Al particles as well as modify the eutectic phase of alloys. In semi-solid die casting, Al7Si0.3Mg alloys with RE concentrations (0, 0.1 and 0.4 wt.%) were used to prepare semi-solid slurries using the SEED (Swirling Enthalpy Equilibrium Device) method, and subsequently semi-solid die cast. The same compositions of alloys were also applied to gravity die casting. The microstructure and mechanical properties of castings in two processes have been characterized. Compared to the grains produced in gravity die casting, globular grains with small size (260 μm) in the semi-solid die casting significantly enhance the UTS and elongation of alloys. Although the size of grains had no change with increasing RE concentrations in alloys. The Al-Si eutectics were changed to refined morphology with the 0.1 wt.% RE addition, which enhanced the ductility of alloys in two processes. When increasing the RE addition to 0.4 wt.%, the RE-rich phases precipitated at grain boundaries, which decreased the UTS and elongation of alloys.

Microstructure and mechanical properties of Mg–Al based alloy with calcium and rare earth additions

2003 ◽  
Vol 356 (1-2) ◽  
pp. 1-7 ◽  
Author(s):  
Du Wenwen ◽  
Sun Yangshan ◽  
Min Xuegang ◽  
Xue Feng ◽  
Zhu Min ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Microstructure And Mechanical Properties ◽  
Rare Earth Additions

Microstructure and Mechanical Properties of Sn-Bi Alloy Treated in the Semi-Solid State by Mechanical Stirring Process

2010 ◽  
Vol 150-151 ◽  
pp. 1768-1771 ◽  
Author(s):  
Feng Li ◽  
Yong Jun Hu ◽  
Xiao Ling Cheng ◽  
Xiao Ting Xiao
Keyword(s):  
Mechanical Properties ◽  
Solid State ◽  
Die Casting ◽  
Percentage Elongation ◽  
Mechanical Stirring ◽  
Microstructure And Mechanical Properties ◽  
Stirring Time ◽  
Microstructures And Mechanical Properties ◽  
Semi Solid

In this work, the effect of stirring time on the solidifed microstructures and mechanical properties of semi-solid Sn-Bi slurry was investigated by the mechanical stirring method. The results indicated that a fine round granular solidifed structure of Sn-Bi semi-solid slurry was obtained at 142 and stirred for 8 min. Compared with the Sn-Bi alloy prepared conventional die casting, the mechamical properties of semi-solid Sn-Bi alloy was improved prominently. The percentage elongation of semi-solid Sn-Bi alloy was increased 67 % compared with that of the Sn-Bi alloy prepared conventional die casting.

Microstructure and Mechanical Properties of Semi-Solid Die-Cast A356 Aluminum Alloy

2016 ◽  
Vol 877 ◽  
pp. 39-44
Author(s):  
Si Min Lei ◽  
Li Gao ◽  
Yohei Harada ◽  
Shinji Kumai
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
A356 Aluminum Alloy ◽  
Microstructure And Mechanical Properties ◽  
Die Cast ◽  
Microstructural Evaluation ◽  
Cast Machine ◽  
A356 Aluminum ◽  
Semi Solid ◽  
The Relationship

The present work deals with the relationship between microstructure and mechanical properties of A356 aluminum alloy which was produced via thixocasting process under different casting conditions. Feedstock billets were heated to a target temperature to obtain a semi-solid slurry with the required solid fraction. Some billets were heated to a fully-melted condition. In order to obtain fine and spheroidized Al grains, some billets for the partially melting were compressed axially by 33% at a room temperature before heating. The completely-melted and partially-melted slurries were die-cast by using a die-cast machine, and hour glass-shaped rod-type tensile specimens and small-size plate-type tensile specimens were obtained. Small cubic specimens were also collected from the die-cast products for microstructural evaluation. They were polished, and etched by Weck’s reagent. The partially-melted specimen which was compressed before heating shows the spherical Al grains. But the grain of the strain-free partially-melted specimen exhibited complicated morphology. The fully-melted specimen shows the fine and dendrite structure.

Microstructure and Mechanical Properties of Low Pressure Die Cast AM50 Magnesium Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 167-170 ◽  
Author(s):  
Li Ming Peng ◽  
Peng Huai Fu ◽  
Hai Yan Jiang ◽  
Chun Quan Zhai
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Die Casting ◽  
Low Pressure ◽  
Microstructure And Mechanical Properties ◽  
Heat Treated ◽  
Die Cast ◽  
Second Phases ◽  
Am50 Alloy ◽  
Pressure Die Casting

Compact AM50 alloy components were cast by Low Pressure Die Casting (LPDC) process. The microstructure and mechanical properties of cast components were investigated under as-cast and heat treated states. It was found that the microstructure of LPDC AM50 is composed of α-Mg and second phases - Mg17Al12 and Al8Mn5. Compared with Gravity die casting, LPDC AM50 alloy had much coarser grains and higher density, with smaller sizes and less content of second phases. The density of AM50 alloy by LPDC process was ρ=1.7836g/cm3, with increase of 0.45% based on Gravity die casting and much more increase compared with high pressure die casting. The as-cast mechanical properties by LPDC process were: σ0.2=57.8Mpa, σb=192.3Mpa, δ=8.7%. These of Gravity die casting were: σ0.2=53Mpa, σb=173.4Mpa, δ=8.1%. UTS in LPDC increased about 20MPa, with better YTS and Elongation. Compared with that of high pressure die cast AM50, the YTS of LPDC was much lower, with comparable UTS and Elongation. The mechanical properties of the heat treated AM50 alloy were still in the same level of as-cast state. AM50 alloy by LPDC process is not necessary subjected to tempering treatment.

Effects of Rare Earth Oxides on Microstructures and Properties of Magnesia Refractories

2008 ◽  
Vol 368-372 ◽  
pp. 1158-1160 ◽  
Author(s):  
Bao Guo Zhang ◽  
Zhou Fu Wang ◽  
Shao Wei Zhang ◽  
Xi Tang Wang ◽  
Zi Wei Xu
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Rare Earth ◽  
High Temperature ◽  
Mechanical Strength ◽  
Grain Boundaries ◽  
Bulk Density ◽  
Rare Earth Oxide ◽  
Rare Earth Oxides ◽  
Microstructure And Mechanical Properties

The effects of Y2O3, La2O3 and Nd2O3 on the sintering, microstructure and mechanical properties of magnesia refractories were investigated. Addition of rare earth oxide (ReO) to magnesia refractories increases the bulk density, decreases the porosity and improves the mechanical strength of the refractories. The improved sinterability was attributable to the vacancies generation associated with the solid-solution reactions between MgO and ReO. In the samples with ReO, rare earth silicate phases form at magnesia grain boundaries, providing additional bonding between magnesia grains and between magnesia grains and matrix. Consequently, the samples with ReO showed much higher high temperature strengths than those without ReO.

Effects of Bismuth on the Microstructure and Mechanical Properties of AlSi9Cu3(Fe) Die Casting Alloys

2013 ◽  
Vol 765 ◽  
pp. 59-63 ◽  
Author(s):  
Stefano Ferraro ◽  
Giulio Timelli ◽  
Alberto Fabrizi
Keyword(s):  
Mechanical Properties ◽  
Trace Element ◽  
Die Casting ◽  
Eutectic Structure ◽  
Al Alloys ◽  
Casting Alloys ◽  
Microstructure And Mechanical Properties ◽  
Die Cast ◽  
Foundry Alloys ◽  
Cast Alloys

In secondary die cast Al alloys, Bismuth is generally considered an impurity element and present as a trace element in commercial foundry alloys. In the present work, the influence of different Bi content on the microstructure and mechanical properties of a commercial die cast AlSi9Cu3(Fe) alloy is investigated. The Bi level ranges between 0.015 and 0.3 wt.%. The results show that the presence of Bi seems to not produce significant changes in the microstructure and mechanical properties. Fine Bi-rich compounds are observed in the die cast alloys and they are mainly distributed in the interdendritic regions and along grain boundaries. TEM investigations revealed a complex Bi-Bi2Mg3eutectic structure, which presents mainly rod-type and blocky morphology.

Effect of Heat Treatment on Microstructure and Mechanical Properties of Semi-Solid Formed Magnesium Alloy AZ91D

2010 ◽  
Vol 148-149 ◽  
pp. 346-352
Author(s):  
Dong Nan Li ◽  
Wen Zhe Chen ◽  
Jun Tian
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Die Casting ◽  
Primary Phase ◽  
T6 Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
Alloy Az91d ◽  
Semi Solid

The semi-solid slurry of AZ91D magnesium alloy was prepared by twin-screw stirring mixer, the microstructure and mechanical properties of semi-solid formed magnesium alloy AZ91D produced by rheo-diecasting and conventional liquid die casting were investigated, respectively. The strengthen mechanism of the semi-solid formed magnesium alloy after heat treatment was analysed by EDS. The results show that the mechanical properties of semi-solid formed magnesium alloy can be enhanced markedly by T4 and T6 heat treatment, owing to decrease of the porosity and less segregation in casting, brittle eutectic compounds dissolves gradually into α-Mg matrix, and the primary phase α-Mg decomposes in the course of heat treatment. In as-cast state, the tensile strength, elongation and hardness of semi-solid formed magnesium alloy AZ91D are 222MPa, 2.3% and 74 HBS, respectively. In T4 heat treatment state, the tensile strength and elongation are increased by 13% and 210%, and in T6 heat treatment state, the tensile strength and hardness are increased by 11% and 16%. The mechanical properties of castings formed by conventional liquid die casting are deteriorated distinctly after T6 heat treatment due to its porosity and crack defects.

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