scholarly journals Effects of Cooling Rate on the Microstructure, Mechanical Properties and Corrosion Resistance of 6xxx Aluminium Alloy

Author(s):  
Joseph Agboola ◽  
Emmanuel Anyoku ◽  
Atinuke Oladoye

The applicability of materials is highly dependent on its microstructure and mechanical properties. Aluminium alloy is being used extensively under diverse conditions. This study investigates the effects of cooling rate on the microstructure, mechanical properties and corrosion resistance of 6xxx-series aluminium alloy. Aluminium ingot was melted in a muffle furnace and cast into rods. The cooling rate was controlled by holding the moulds at different temperatures.  Microstructural characteristics were examined by optical microscopy. Mechanical properties such as impact strength, hardness, and tensile strength were analysed using standard methods. Corrosion resistance was evaluated by potentiodynamic polarization. It was found that microstructures are dominated by ferrite and pearlite phases with different morphologies and grain sizes depending on the cooling rate.  Increasing the cooling rate resulted in microstructural refinement and chemical homogeneity, improvement in mechanical properties and corrosion resistance of the 6xxx alloy.

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1421 ◽  
Author(s):  
Zhenzhen Gui ◽  
Junyi Zhang ◽  
Zhixin Kang

The differences in microstructural characteristics, mechanical properties, and corrosion behavior of the as-cast and solution-treated Mg-xGd-1.5Nd-0.5Zn-0.5Zr alloys (Mg-xGd, x = 1, 3, and 5) were studied and discussed. The as-cast Mg-xGd alloys mainly consisted of an α-Mg and island-like eutectic (Mg,Zn)3RE phase, a few cuboidal phases (REH2), and a ZnZr phase. With the increase of Gd content, the grain sizes of the as-cast Mg-xGd alloys decreased. Compared to the microstructure of the as-cast Mg-xGd alloys, the eutectic (Mg,Zn)3RE phase disappeared and the cuboidal REH2 phases existed in the solution-treated Mg-xGd alloys. A large amount of ZnZrx phase was precipitated from α-Mg in the Mg-3Gd alloy and demonstrates a flower-like distribution. The ultimate tensile strength (UTS) and yield strength (YS) of the solution-treated Mg-xGd alloys increased with an increasing Gd content, with the UTS and YS of the Mg-5Gd alloys reaching 217.5 and 125.2 MPa, respectively. Immersion and electrochemical tests showed that the as-cast Mg-3Gd alloy presented the best corrosion resistance with a corrosion rate of 0.285 mm/yr. The corrosion resistance of the solution-treated Mg-3Gd alloy attained the lowest value (0.973 mm/yr), due to the large quantities of ZnZrx with a flower-like phase distribution, forming series of galvanic couple groups with the α-Mg.


Alloy Digest ◽  
1993 ◽  
Vol 42 (11) ◽  

Abstract REMANIT 4439 is a highly corrosion resistant steel with low carbon content, an addition of nitrogen to enhance both mechanical properties and corrosion resistance, and higher molybdenum than most stainless steels to resist pitting and crevice corrosion in chloride media. This datasheet provides information on composition, physical properties, and elasticity. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-556. Producer or source: Thyssen Stahl AG.


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3675
Author(s):  
A. Muthuchamy ◽  
Muthe Srikanth ◽  
Dinesh K. Agrawal ◽  
A. Raja Annamalai

In this research, we intended to examine the effect of heating mode on the densification, microstructure, mechanical properties, and corrosion resistance of sintered aluminum alloys. The compacts were sintered in conventional (radiation-heated) and microwave (2.45 GHz, multimode) sintering furnaces followed by aging. Detailed analysis of the final sintered aluminum alloys was done using optical and scanning electron microscopes. The observations revealed that the microwave sintered sample has a relatively finer microstructure compared to its conventionally sintered counterparts. The experimental results also show that microwave sintered alloy has the best mechanical properties over conventionally sintered compacts. Similarly, the microwave sintered samples showed better corrosion resistance than conventionally sintered ones.


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