Mechanical properties of friction stir welded aluminum alloys 5083 and 5383

Paik, Jeom-Kee The Society of Naval Architects of Korea 2009 International Journal of Naval Architecture and Oc Vol.1 No.1

The use of high-strength aluminum alloys is increasing in shipbuilding industry, particularly for the design and construction of war ships, littoral surface craft and combat ships, and fast passenger ships. While various welding methods are used today to fabricate aluminum ship structures, namely gas metallic arc welding (GMAW), laser welding and friction stir welding (FSW), FSW technology has been recognized to have many advantages for the construction of aluminum structures, as it is a low-cost welding process. In the present study, mechanical properties of friction stir welded aluminum alloys are examined experimentally. Tensile testing is undertaken on dog-bone type test specimen for aluminum alloys 5083 and 5383. The test specimen includes friction stir welded material between identical alloys and also dissimilar alloys, as well as unwelded (base) alloys. Mechanical properties of fusion welded aluminum alloys are also tested and compared with those of friction stir welded alloys. The insights developed from the present study are documented together with details of the test database. Part of the present study was obtained from the Ship Structure Committee project SR-1454 (Paik, 2009), jointly funded by its member agencies.

Mechanical Properties of Friction Stir Welded Aluminum Alloys 5083 and 5383

백점기 대한조선학회 2009 International Journal of Naval Architecture and Oc Vol.1 No.1

The use of high-strength aluminum alloys is increasing in shipbuilding industry, particularly for the design and construction of war ships, littoral surface craft and combat ships, and fast passenger ships. While various welding methods are used today to fabricate aluminum ship structures, namely gas metallic arc welding (GMAW), laser welding and friction stir welding (FSW), FSW technology has been recognized to have many advantages for the construction of aluminum structures, as it is a low-cost welding process. In the present study, mechanical properties of friction stir welded aluminum alloys are examined experimentally. Tensile testing is undertaken on dog-bone type test specimen for aluminum alloys 5083 and 5383. The test specimen includes friction stir welded material between identical alloys and also dissimilar alloys, as well as unwelded (base) alloys. Mechanical properties of fusion welded aluminum alloys are also tested and compared with those of friction stir welded alloys. The insights developed from the present study are documented together with details of the test database. Part of the present study was obtained from the Ship Structure Committee project SR-1454 (Paik, 2009), jointly funded by its member agencies.

Warm Temperature Deformation Behavior and Processing Maps of 5182 and 7075 Aluminum Alloy Sheets with Fine Grains

D. H. Jang,W. J. Kim 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.3

The tensile deformation behavior and processing maps of commercial 5182 and 7075 aluminum alloy sheets with similarlyfi ne grain sizes (about 8 μm) were examined and compared over the temperature range of 423–723 K. The 5182 aluminumalloy with equiaxed grains exhibited larger strain rate sensitivity exponent ( m ) values than the 7075 aluminum alloy withelongated grains under most of the testing conditions. The fracture strain behaviors of the two alloys as a function of strainrate and temperature followed the trend in their m values. In the processing maps, the power dissipation parameter valuesof the 5182 aluminum alloy were larger than those of the 7075 aluminum alloy and the instability domains of the 5182aluminum alloy were smaller compared to that of the 7075 aluminum alloy, implying that the 5182 aluminum alloy had abetter hot workability than the 7075 aluminum alloy.

A Review of Joining Processes for High Strength 7xxx Series Aluminum Alloys

Minjung Kang,Cheolhee Kim 대한용접·접합학회 2017 대한용접·접합학회지 Vol.35 No.6

The applications of high strength aluminum alloys in automobile manufacturing has been growing with increasing demands for fuel efficiency and reduction of CO₂ emissions. Aluminum alloys pair a high specific strength with relatively low cost compared to similar lightweight metals. The 7XXX series aluminum alloys in particular exhibit a high strength in excess of 500 MPa after heat treatment. However, these alloys exhibit poor weldability because of their high crack susceptibility, high thermal expansion coefficient, and low vaporization-temperature of alloying elements such as Zn and Mg, which readily contributes to weld defects such as cracks and porosity. In this paper, the mechanical properties and microstructural characteristics of 7XXX aluminum alloys are related to welding processes and reviewed for better understanding of the welding characteristics of this high strength alloy.

Adhesion with Aluminum for Material Surfaces Additively Manufactured by Directed Energy Deposition

Ju‑Young Jeong,Hyun‑Sung Kang,Su‑Ho Kim,Ki‑Yong Lee,Dong‑Ju Kim,Dosik Shim 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.6

The adhesion of aluminum to molds or tools is common during the production of aluminum alloy products for vehicle light weighting. It reduces the productivity and quality, and thus, it needs to be prevented. This study attempted to use directed energy deposition (DED) to deposit a heterogeneous material on the surface of a mold material to prevent the aluminum adhesion. The powders used in the heterogeneous material deposition included the Fe-based alloys D2 and H13, Ni-based alloy Inconel718, and Co-based alloy Stellite21. Immersion tests and wear tests were performed to test the deposits’ reactivity with aluminum. After the immersion of deposited samples into melted aluminum, the smallest amount of adhesion was observed on the D2 surface. The H13-deposited zone had the highest value of hardness. However, the hardness of the deposited surface did not display a close relationship with aluminum adhesion. In addition, the H13- and Stellite21-deposited zones displayed high thermal conductivity compared with the other two specimens. The microimages and elemental analyses revealed that the adhesion was formed owing to metallurgical fusion. During the wear tests, the temperature increased owing to the friction between the aluminum pins and deposited specimens. Stellite21 and H13 produced a smaller temperature increase than Inconel718 and D2. From the wear test, it was observed that the aluminum pin material adhered to the wear specimen surface for the D2-, H13- and Inconel718-deposited specimens. Thick aluminum adhesion layers were formed in the case of the D2 and Inconel718 specimens. Nevertheless, aluminum adhesion could not be observed on the Stellite21 specimen’s surface, whereas typical wear scars caused by wearing were apparent. It can be concluded that adhesion with aluminum varies according to the alloy elements contained in the metal alloy as well as the thermal conductivity of the deposited materials.

The Effect of Pre-strain and Subsequent Electrically Assisted Annealing on the Mechanical Behaviors of Two Different Aluminum Alloys

Kieu-Anh Dinh,Sung-Tae Hong,Seung-Jun Choi,김문조,Heung Nam Han 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.12

The effects of pre-strain and subsequent electrically assisted annealing on the mechanical behaviors of two different (Al–Mg and Al–Si–Mg) aluminum alloys during electrically assisted dual stage forming are experimentally investigated. First, a specimen is deformed to a specific pre-strain by uniaxial tension and then automatically unloaded. After that, the pre-strained specimen is subjected to electrically assisted annealing by electric current with a fixed subsecond duration. Finally, the specimen is reloaded until fracture. Experimental results show that application of electric current with a subsecond duration induces electrically assisted annealing to both pre-strained aluminum alloys. The electric current also increases total achievable elongation until fracture during electrically assisted dual stage forming for both aluminum alloys. However, analysis of the stress–strain behavior during reloading and microstructural observations suggest that the quantitative effects of electric current on the post-electrically assisted annealing mechanical behavior and resultant microstructure are strongly dependent on the type of aluminum alloy. With the electric current density of 140 A/mm 2 , a full recrystallization followed by grain growth occurs in the pre-strained Al–Mg alloy specimens. For the pre-strained Al–Mg–Si alloy specimens, the electric current density of 140 A/mm 2 induces both annealing and solid solutioning. Together, our findings indicate that while electrically assisted annealing is effective at improving the productivity of dual stage forming of an aluminum alloy, the composition of the aluminum alloy should be carefully considered in the design of forming process utilizing the concept of electrically assisted annealing since the beneficial effect was limited for the precipitation hardening 6061-T6 aluminum alloy.

전자기 듀오캐스팅으로 제조한 Al-Mn/Al-Si 하이브리드 알루미늄합금의 미세조직과 인장 특성

박성진,김종호,박준표,장시영,Park, Sung-Jin,Li, Tingju,Kim, Chong-Ho,Park, Jun-Pyo,Chang, Si-Young 한국재료학회 2012 한국재료학회지 Vol.22 No.2

The microstructure and tensile properties of Al-Mn/Al-Si hybrid aluminum alloys prepared by electromagnetic duocasting were investigated. Only the Al-Mn alloy showed the typical cast microstructure of columnar and equiaxed crystals. The primary dendrites and eutectic structure were clearly observed in the Al-Si alloy. There existed a macro-interface of Al-Mn/Al-Si alloys in the hybrid aluminum alloys. The macro-interface was well bonded, and the growth of primary dendrites in Al-Si alloy occurred from the macro-interface. The Al-Mn/Al-Si hybrid aluminum alloys with a well-bonded macro-interface showed excellent tensile strength and 0.2% proof stress, both of which are comparable to those values for binary Al-Mn alloy, indicating that the strength is preferentially dominated by the deformation of the Al-Mn alloy side. However, the degree of elongation was between that of binary Al-Mn and Al-Si alloys. The Al-Mn/Al-Si hybrid aluminum alloys were fractured on the Al-Mn alloy side. This was considered to have resulted from the limited deformation in the Al-Mn alloy side, which led to relatively low elongation compared to the binary Al-Mn alloy.

Research on the Mechanical Properties of Some New Aluminum Alloy Composite Structures in Construction Engineering

Mengting Fan,Xuan Wang 한국재료학회 2024 한국재료학회지 Vol.34 No.2

The lightweight and high strength characteristics of aluminum alloy materials make them have promising prospects in the field of construction engineering. This paper primarily focuses on aluminum alloy materials. Aluminum alloy was combined with concrete, wood and carbon fiber reinforced plastic (CFRP) cloth to create a composite column. The axial compression test was then conducted to understand the mechanical properties of different composite structures. It was found that the pure aluminum tube exhibited poor performance in the axial compression test, with an ultimate load of only 302.56 kN. However, the performance of the various composite columns showed varying degrees of improvement. With the increase of the load, the displacement and strain of each specimen rapidly increased, and after reaching the ultimate load, both load and strain gradually decreased. In comparison, the aluminum alloy-concrete composite column performed better than the aluminum alloy-wood composite column, while the aluminum alloy-wood-CFRP cloth composite column demonstrated superior performance. These results highlight excellent performance potential for aluminum alloy-wood-CFRP composite columns in practical applications.

Castability and mechanical properties of new 7xxx aluminum alloys for automotive chassis/body applications

Shin, Jesik,Kim, Taehyeong,Kim, DongEung,Kim, Dongkwon,Kim, Kitae Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.698 No.-

<P><B>Abstract</B></P> <P>To develop an aluminum alloy that combines excellent mechanical properties with good castability for near-net-shape casting of automotive structural parts, new Cu–free medium Mg 7xxx aluminum alloys with minor Zr (0.1%) and Ti (0, 0.1, and 0.2%) (all contents in wt% unless stated otherwise) elemental content were investigated as potential candidates. The effects of a vulnerable temperature interval and grain refinement on the hot tearing susceptibility (HTS) were investigated in this work to prevent hot tearing. Al–6Zn–(1.3–1.5)Mg–0.1Zr–(0.1–0.2)Ti alloys show 140–150% of ultimate tensile strength (370–390 MPa), 150–180% of elongation (10–12%), 60–80% of medium-thick-wall fluidity, and equivalent thin-wall fluidity, compared to the respective properties of the commercial A356 alloy. Medium-thick-wall fluidity depended on the heat release upon solidification of the alloy investigated, and thin-wall fluidity depended on the surface energy of the alloy in molten state. When the Ti content was increased, a concave variation in the medium-thick-wall fluidity and a monotonic increase in the thin-wall fluidity were observed. In terms of hot tearing, Ti addition led to a decrease in the HTS, which eventually reached zero. By adding 3% Si, hot tearing could be prevented; however, at the same time, elongation was found to decrease to less than 4%. The grain size reduction and morphology alteration due to the combined addition of 0.2% Ti and 0.1% Zr led to an improvement in castability because of a delay in crystal coherency, decrease in solidification time and vulnerable time period, and suppression of Fe-containing intermetallic and T phase crystallization.</P> <P><B>Highlights</B></P> <P> <UL> <LI> New Cu–free medium Mg 7xxx aluminum alloys with minor Ti and Zr are investigated. </LI> <LI> These alloys show an excellent combination of strength, ductility, and castability. </LI> <LI> With increasing Ti content up to 0.2%, the HTS decreases, eventually reaching zero. </LI> <LI> The addition of 0.2% Ti–0.1% Zr improves alloy fluidity and prevents hot tearing. </LI> <LI> The mechanisms of fluidity and HTS dependence on Mg, Si and Ti contents are proposed. </LI> </UL> </P>

Development and characterization of low-silicon cast aluminum alloys for thermal dissipation

Shin, Je-Sik,Ko, Se-Hyun,Kim, Ki-Tae Elsevier 2015 Journal of alloys and compounds Vol.644 No.-

<P><B>Abstract</B></P> <P>Two low-silicon quaternary aluminum alloys, Al–(0.5–1.5)Mg–1Fe–0.5Si and Al–(1.0–1.5)Si–1Fe–1Zn, are investigated for their potential to combine a high thermal conductivity with good castability and anodizability. By comparing to the physical and casting properties of the commercial ADC12 alloy, the developed alloys show 170–190% of thermal conductivities (160–180W/mK), a similar medium-thick-wall fluidity, 60–85% of thin-wall fluidity, 100–130% of hot tearing susceptibility (HTS), and a comparable ultimate tensile strength. As Mg and Si, the major alloying elements, increase, the thermal conductivity decreases and the strength increases. The thin-wall fluidity and the HTS are both inversely proportional to the Mg content and directly proportional to the Si content. These opposite trends within the two alloy systems arise mainly from differences in the Al dendrite coherency and first intermetallic crystallization points, and in the crystallization behavior of β-AlFeSi phase. The lower viscosity and lower surface energy of the Al–(0.5–1.5)Mg–1Fe–0.5Si and Al–(1.0–1.5)Si–1Fe–1Zn alloys, respectively enhance their fluidity in thicker and thinner sections. A large fluidity sensitivity to the channel diameter of the aluminum alloys developed here is attributed to their higher melting points, lower latent heats, and higher formation tendency of oxide films and inclusions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Al–<I>x</I>Mg–1Fe–0.5Si and Al–<I>x</I>Si–1Fe–1Zn alloys are investigated for thermal dissipation. </LI> <LI> Their thermal conductivity and castability are compared to those of ADC12 alloy. </LI> <LI> These alloys show superior thermal conductivity (up to 180W/mK, 190% that of ADC12). </LI> <LI> These alloys show similar medium-thick-wall and slightly inferior thin-wall fluidity. </LI> <LI> The variation mechanisms of fluidity and HTS with Mg and Si contents are proposed. </LI> </UL> </P>