The Important Role of Dissolved Elements (Mn, Fe) in the Process of Rolled Products and Their Effects on Final Properties
Abstract:
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The important role of dissolved elements, such as manganese or iron, in the production process of
rolled material was in the focus of this investigation.
In the AlMn-alloys the content of manganese in solid solution is first controlled by other alloying
elements such as silicon and iron. The addition of silicon or / and iron reduces the level of
manganese in solid solution in the as-cast condition as well as in the following preheating process
step. Another major parameter is the final annealing treatment of the rolled products. The
preheating treatment and the final annealing are the key parameters to control the level of
manganese in solid solution and the size and distribution of the fine dispersoids.
In the AlFe-series alloys the iron content in solid solution is first controlled by the casting process
DC or CC and the amount of iron in the alloy composition. In the as-cast condition the dissolved
iron level is normally higher in the CC-material than in the DC-material. The intermediate
annealing treatment also has a great influence on the content of iron in solid solution.
They recovery and recrystallisation behaviour is controlled by the content of manganese or iron in
solid solution. The precipitation of manganese or iron during thermal treatment leads to optimum
dislocation pinning and results in a high thermal stability. On the other hand, if the precipitation of
manganese or iron interacts with the occurence of recrystallisation, the resulting grain structure can
show coarse grain.
J. Hasenclever "The Important Role of Dissolved Elements (Mn, Fe) in the Process of Rolled Products and Their Effects on Final Properties", Materials Science Forum, Vols. 519-521, pp. 1447-1452, 2006
Authors: M. Kolář, Vladivoj Očenášek, J. Uhlíř, Ivana Stulíková, Bohumil Smola, Martin Vlach, V. Neubert, K. Šperlink
Abstract: The influence of plastic deformation and heat-treatment on the precipitation of Al3(Sc,
Zr) particles and the effect of these precipitates on hardening and softening processes of dilute
ternary Al-0.2wt.%Sc-0.1wt.%Zr alloy was investigated. Behaviour of two differently prepared
alloys (mold cast and prepared by powder metallurgy – PM) was investigated in as-prepared and in
cold rolled state. Both alloys exhibit the same peak age hardening, PM one reaches it already during
extrusion at 350°C. Both cold rolled alloys are highly resistant against recovery, which proceeds
without rapid hardness decrease at high temperatures. Evolution of hardness agrees well with that of
resistivity and with TEM observation.
Authors: E.P. Masuku, Gonasagren Govender, L. Ivanchev, Heinrich Möller
Abstract: Rheocasting of alloys A206 and A201 was investigated in this study. Conical bars with
different silver contents were produced using CSIR rheoprocess technology, together with high
pressure die casting. The results showed that addition of Ag to alloy A206 increased the mechanical
properties of the alloy. However, the addition of Ag also resulted in Cu-rich phases to precipitate at
the grain boundaries of the as-cast material. The solution treatment used in this study was unable to
dissolve all of this phase, especially in the 1.12%Ag-containing alloy. This resulted in slightly
decreased mechanical properties compared to the 0.63%Ag-containing alloy. The T6 mechanical
properties (strength and elongation) obtained in this study for rheocast A206 and A201 are better
than those reported for permanent mould castings of alloy A206 and A201.
Authors: Bao Hong Zhu, Bai Qing Xiong, Yon Gan Zhang, Udo Fritsching, Ji Shan Zhang, Feng Wang, Zhi Hui Li, Hong Wei Liu
Abstract: A high Zn content Al-Zn-Mg-Cu alloy was prepared by spray forming process and the precipitate behavior and microstructure of the extruded alloy were also investigated. The precipitate sequence of the spray-formed alloy could be described as “α-solid solution → GPI zone → GPII zone (also called Metastable ′ )→ Stable (MgZn2)” during artificial ageing treatment. In the early stage of artificial ageing treatment, the GPI zone was the main strengthening phase and kept coherent relationship with the matrix. With the increasing of ageing time, ′ phase dominate strengthening phase and kept semi-coherent relationship with the matrix. With the further increasing of ageing time, phase took the place of ′ phase, and dominated the strengthening phase in the alloy. The grain size of the spray deposit is finer than that of cast alloys. The ultimate tensile strength of the alloy is over 810MPa in peak ageing condition.
Abstract: Effects of hydrogenation process of the microstructure, electrical conductivity and mechanical properties for the Cu-(1~3) mass%Ti alloys were investigated. During hydrogenation process at 350°C, 7.5 MPa for 48 h, the disproportionation reaction occurred with forming of Ti hydrides in the alloy. It is found that remarkable simultaneous improvements of mechanical strength of 1094 MPa and electrical properties of 21%IACS are obtained in the hydrogenated Cu-3mass%Ti alloy.
Authors: Xiao Ping Luo, Lan Ting Xia, Ming Gang Zhang
Abstract: The effect of Cd and Sb addition on the microstructural and mechanical properties of as-cast AZ31 alloys was investigated and compared. The results indicate that the difference of Sb and Cd in the microstructure and mechanical properties of as-cast AZ31 magnesium alloy is significant. Addition of 0.15%Sb (mass fraction) to AZ31 alloy can refine the matrix and β-Mg17Al12 phase but not form a new phase Mg3Sb2. Oppositely, by addition of 0.3-0.7% Cd to AZ31 alloy, Cd was dissolved into the AZ31 alloy, the phase composition did not change but was refined also. Accordingly, the Cd-refined AZ31 alloy exhibits higher tensile and impact toughness and Brinell hardness properties than the Sb- refined one. The difference of Sb and Cd in the mechanical properties is possibly related to the solid solution of Cd into the matrix and formation of Mg3Sb2 which has the same close-packed hexagonal structure as α-Mg.