scholarly journals Effect of Al2Ca Addition and Heat Treatment on the Microstructure Modification and Tensile Properties of Hypo-Eutectic Al–Mg–Si Alloys

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4588
Author(s):  
Abdul Wahid Shah ◽  
Seong-Ho Ha ◽  
Bong-Hwan Kim ◽  
Young-Ok Yoon ◽  
Hyun-Kyu Lim ◽  
...  

The current study investigated the microstructure modification in Al–6Mg–5Si–0.15Ti alloy (in mass %) through the minor addition of Ca using Mg + Al2Ca master alloy and heat treatment to see their impact on mechanical properties. The microstructure of unmodified alloy (without Ca) consisted of primary Al, primary Mg2Si, binary eutectic Al–Mg2Si, ternary eutectic Al–Mg2Si–Si, and iron-bearing phases. The addition of 0.05 wt% Ca resulted in significant microstructure refinement. In addition to refinement, lamellar to fibrous-type modification of binary eutectic Al–Mg2Si phases was also achieved in Ca-added (modified) alloy. This modification was related to increasing Ca-based intermetallics/compounds in the modified alloy that acted as nucleation sites for binary eutectic Al–Mg2Si phases. The dendritic refinement with Ca addition was related to the fact that it improves the efficacy of Ti-based particles (TiAl3 and TiB2) in the melt to act as nucleation sites. In contrast, the occupation of oxide bifilms by Ca-based phases is expected to force the iron-bearing phases (as iron-bearing phases nucleate at oxide films) to solidify at lower temperatures, thus reducing their size. The as-cast microstructure of these alloys was further modified by subjecting them to solution treatment at 540 °C for 6 h, which broke the eutectic structure and redistributed Mg2Si and Si phases in Al-matrix. Subsequent aging treatment caused a dramatic increase in the tensile strength of these alloys, and tensile strength of 291 MPa (with El% of 0.45%) and 327 MPa (with El% of 0.76%) was achieved for the unmodified alloy and modified alloy, respectively. Higher tensile strength and elongation of the modified alloy than unmodified alloy was attributed to refined dendritic structure and modified second phases.

2006 ◽  
Vol 114 ◽  
pp. 91-96 ◽  
Author(s):  
Maxim Yu. Murashkin ◽  
M.V. Markushev ◽  
Julia Ivanisenko ◽  
Ruslan Valiev

The effects of equal channel angular pressing (ECAP), further heat treatment and rolling on the structure and room temperature mechanical properties of the commercial aluminum alloys 6061 (Al-0.9Mg-0.7Si) and 1560 (Al-6.5Mg-0.6Mn) were investigated. It has been shown that the strength of the alloys after ECAP is higher than that achieved after conventional processing. Prior ECAP solution treatment and post-ECAP ageing can additionally increase the strength of the 6061 alloy. Under optimal ageing conditions a yield strength (YS) of 434 MPa and am ultimate tensile strength (UTS) of 470 MPa were obtained for the alloy. Additional cold rolling leads to a YS and UTS of 475 and 500 MPa with 8% elongation. It was found that the post-ECAP isothermal rolling of the 1560 alloy resulted in the formation of a nano-fibred structure and a tensile strength (YS = 540 MPa and UTS = 635 MPa) that has never previously been observed in commercial non-heat treatable alloys.


2013 ◽  
Vol 690-693 ◽  
pp. 44-48
Author(s):  
Feng Wang ◽  
Zhi Wang ◽  
Zheng Liu ◽  
Ping Li Mao

In this paper, developed a non-aluminum die casting magnesium alloys were studied based on Mg-xGd-Y-Zr(x=6, 8, 12 wt.%)alloys in cold chamber press. The microstructures and mechanical properties of die casting GWK alloys have been investigated using OM, SEM, XRD, EDS and mechanical property test. The experimental results show that with increasing Gd content of Mg-xGd-Y-Zr alloys, the tensile strength increase, but elongation decrease. In particular, die casting GWK alloys after short-term and low-temperature solid solution treatment (T4) have a small variation in grain size and more uniform microstructures, and the second phases distribute at the grain boundaries in form of discontinuous rod shape or granule shape, which result in an obvious improvement in tensile mechanical properties of alloys. The Mg-12Gd-3Y-0.5Zr die casting alloy exhibit maximum tensile strength after solution heat treatment, and the value is 269MPa at room temperature. The effect of solution heat treatment on die casting Mg-xGd-Y-Zr alloys was also discussed.


2011 ◽  
Vol 467-469 ◽  
pp. 257-262
Author(s):  
Guo Fa Mi ◽  
Jin Zhi Zhang ◽  
Hai Yan Wang

Alloys were produced by casting of Cu-Al-Fe-Be and Cu-Al-Fe-Ni aluminum bronzes and aged. The microstructures and mechanical properties were evaluated. The results indicated that solution and aging treatment can significantly improve the plasticity of Cu-Al-Fe-Be and Cu-Al-Fe-Ni, while the strength and hardness remained in the quenched level. Extending the aging time can effectively enhance the mechanical properties of alloys, and the longer the aging time, the higher the electric resistance of alloys. According to the results, the mechanical properties of the Cu-Al-Fe-Be alloy can be improved remarkably by solution treatment for 120 min at 950°C, followed by aging treatment for 120 min at 350°C, and quenched. While the most suitable heat treatment for the Cu-Al-Fe-Ni alloy was solution treatment 120 min at 950°C, followed by aging for 120 min at 450°C, and quenched. The experimental result also suggested that the Cu-Al-Fe-Be alloy possessed higher hardness and tensile strength compared to the Cu-Al-Fe-Ni alloy.


2011 ◽  
Vol 197-198 ◽  
pp. 1125-1128 ◽  
Author(s):  
Jing Jiang Nie ◽  
Liang Meng ◽  
Xiu Rong Zhu ◽  
Yong Dong Xu ◽  
Yue Yi Wu ◽  
...  

The effect of the combined action of hot work and heat treatment on the microstructure and mechanical properties of a Mg-2Gd-Nd-0.4Zn-0.3Zr (wt. %) (E21) alloy was investigated. Results showed that the solution treatment time of the ingot played a great effect on the mechanical properties of the extruded alloy. With solution treating time of the ingot increasing, the tensile strength of the extruded alloy decreased gradually, but the elongation increased greatly. The best combination of strength and ductility was achieved for the extruded alloy after the ingot solution treated at 520°C for 3 h, extrusion at 400°C and aging at 200°C for 16 h, namely ultimate tensile strength = 331MPa and elongation = 7.1%.


2012 ◽  
Vol 466-467 ◽  
pp. 111-115
Author(s):  
Jian Xin Zhang ◽  
Shui Jun Shao ◽  
Liang Li

The effects of Cu element on properties of Al-Mg-Si aluminum alloy was studied, and the mechanism of Cu in influencing the property of the alloy was discussed. The results indicate that Cu element can weaken the conductivity property of alloy material, its thermal conductivity is improved with slow cooling. Cu element is sensitive to corrosive property of the alloy, it can cause corrosion resistance decreasing significantly, quenching heat treatment made corrosive property of the material deteriorative. Proper Cu element is helpful to microstructure refinement and the enhancement of strength, tensile strength of the material is increased 10 percent after solution treatment and ageing strengthening.


2014 ◽  
Vol 14 (4) ◽  
pp. 35-38
Author(s):  
Z. Górny ◽  
S. Kluska-Nawarecka ◽  
E. Czekaj ◽  
D. Wilk-Kołodziejczyk

Abstract The object of the experimental studies was to determine the mechanical properties of a hypoeutectic EN AC - 42100 (EN ACAlSi7Mg0,3) silumin alloy, where the said properties are changing as a result of subjecting the samples of different types to solution treatment. An important aspect of the studies was the use type of device for the heat treatment. As a basic parameter representing the mechanical properties, the tensile strength of the metal (Rm) was adopted.


2011 ◽  
Vol 219-220 ◽  
pp. 195-201 ◽  
Author(s):  
Guo Fa Mi ◽  
Jin Zhi Zhang ◽  
San Lei Lv ◽  
Ping Wang

Wear behaviour of aged casting Cu-Al-Fe-Be and Cu-Al-Fe-Ni aluminum bronzes was studied in this paper. The microstructures, mechanical properties of hardness and tensile strength, were evaluated experimentally. The friction and wear resistance, and the electrical resistivity of the materials were assessed. The results show that mechanical properties of the Cu-Al-Fe-Be alloy have been improved by solution treatment at 950°C for 120 min followed by aging at 350°C for 120 min, whilst the most suitable heat treatment for the Cu-Al-Fe-Ni alloy was solution treatment at 950°C for 120 min followed by aging at 450°C for 120 min. In the wear testing, the as-cast alloys was dominated by abrasive wear, and the increase in load and sliding velocity, the adhesive wear and oxidation wear dominated. The experimental results also showed that the Cu-Al-Fe-Be alloy possessed higher hardness and tensile strength, lower friction coefficient and lower wear rate compared to the Cu-Al-Fe-Ni alloy.


2011 ◽  
Vol 311-313 ◽  
pp. 283-286 ◽  
Author(s):  
R. Khorshidi ◽  
A. Honarbakhsh Raouf ◽  
M. Emamy ◽  
H.R. Jafari Nodooshan

The effect of different solution temperatures has been investigated on the tensile properties of Na-modified Al-Mg2Si in situ composite specimens which were subjected to solutionizing at different temperatures of 480 °C, 500 °C and 520 °C for holding time of 4 h followed by quenching. Tensile test results indicated that elongation value gradually increases upon solution treatment whereas ultimate tensile strength (UTS) reduces. The results of solution treatment also showed that the highest quality index is achieved in 500 °C (354 MPa) and so it is revealed optimum solutionizing temperature level (500 °C) for improving tensile properties.


2012 ◽  
Vol 562-564 ◽  
pp. 242-245 ◽  
Author(s):  
Ming Tan ◽  
Zhao Ming Liu ◽  
Gao Feng Quan

The effects of heat treatment on the microstructure, tensile property and fracture behavior of as-extruded AZ91 magnesium alloy were studied by OM and SEM. The results show that the grain of as-cast AZ91 alloy is refined by extruding and dynamic recrystallization, and the mechanical properties increase obviously. The ductility is significantly enhanced after solution treatment of the as-extruded AZ91 alloy, tensile strength is almost the same before and hardness is significantly reduced after solution treatment and artificial aging treatment. The tensile strength reduced and the ductility is significantly enhanced of as-extruded AZ91 magnesium alloy after annealing processes. The fracture surface of as-extruded AZ91 magnesium alloy has the mixture of ductile and brittle characteristic. But after T6 or annealing treatment, its dimple number increases evidently.


Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 410 ◽  
Author(s):  
Dohyung Kim ◽  
Taehwan Kim ◽  
Kyeongsik Ha ◽  
Jeong-Jung Oak ◽  
Jong Bae Jeon ◽  
...  

18Ni-300 maraging steel produced by the selective laser melting (SLM) process has a unique microstructure that is different from that of the same alloy processed by conventional methods. In this paper, maraging steels were fabricated by the selective laser melting process and their microstructures and mechanical properties were investigated in terms of post heat treatment conditions. Moreover, the effect of different heat treatments on the mechanical anisotropy was studied in detail. The micro Vickers hardness in the as-built state was around 340 Hv and could be increased to approximately 600 Hv by aging heat treatments. It was found that the solution heat treatment was not necessary to obtain a fully hardened state. From tensile tests of the maraging steels heat treated with different conditions, it was found that the highest strength was achieved by aging and solution treatment (ST) temperatures lower than the commonly used temperatures. In the direction parallel to the laser scanning, the highest ultimate tensile strength was obtained when 450 °C aging was done without solution heat treatment. In the other two directions tested, i.e., directions normal to the building and 45 degrees to the laser scanning direction, the highest tensile strength was obtained when aging was done at 450 °C after 750 °C solution treatment.


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