scholarly journals On the Development of an Al4.8 wt% Cu Alloy Obtained from Recycled Aluminum Cans Designed for Thixoforming Process

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Ronan Miller Vieira ◽  
Gianni Ferreira Alves Moreira ◽  
André Itman Filho ◽  
Estéfano Aparecido Vieira

This work has focused on the development of a new aluminum alloy containing 4.8 wt% of Cu alloy obtained from recycled aluminium cans designed for thixoforming process. After the step of melting and solidification of the alloy in a metallic permanent mold, samples were solution heat treated at 525°C for times ranging from 2 h to 48 h, quenched in water and followed by natural aging. Results have shown the evolution of hardness so from them solubilization solution heat treatment was chosen for 24 h. The best condition for aging was 190°C during 3 h. With this data pieces were thixoforged at 580°C and 615°C corresponding, respectively, to solid fraction (fs) of 0.8 and 0.6. The optimized T6 temper was applied and tensile tests were performed. The mechanical properties obtained are compatible with those obtained for consolidated alloys processed in semisolid state (SS) and after T6 temper hardness increases from 95 HB to 122 HB and the best results were a tensile strength of 324 MPa ± 10 MPa, yield strength of 257 MPa ± 18 MPa, and an elongation of 7.1%  ±  1%. For alloys designed for thixoforming process, these results are in accordance with what was expected whereas globular microstructure, high ductility, and good performance under cyclic conditions are desirable.

2017 ◽  
Vol 79 (5-2) ◽  
Author(s):  
Mohd Shukor Salleh ◽  
Mohd Azizul Hikmi Safian ◽  
Mohamad Ridzuan Mohamad Kamal ◽  
Zolkarnain Marjom ◽  
Saifudin Hafiz Yahaya ◽  
...  

Thixoforming is a type of semisolid metal (SSM) processing for forming alloys in the semisolid state to near net-shaped products. In the present study, the effect of a thixoforming process on the microstructure and mechanical properties of Al-6Si-3Cu aluminium alloy was investigated. Melt was poured on a cooling slope at 630oC and the samples were obtained through permanent mold casting. They were thixoformed using a hydraulic press after holding at 571oC for 5min to yield a microstructure predominantly composed of α-Al globules and inter-globular Si particles. As-cast and thixoformed samples were characterized using optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) as well as hardness measurements and tensile tests. The results indicate that the mechanical properties of thixoformed alloy have improved as compared to permanent mold cast alloy. The ultimate tensile strength of as-cast sample was 210 ± 3.5 MPa and increased to 241 ±3.1 MPa in the thixoformed sample while the yield strength of as-cast alloy was 140 ±4.5 MPa and increased to 176±3.3 MPa in the thixoformed sample. The thixoformed alloy also showed an improvement in elongation to fracture as it increased from 2% in as-cast sample to 3.2% in thixoformed alloy. The fracture of as-cast sample showed a cleavage fracture, whereas in the thixoformed alloy, a combination of dimple and cleavage was observed.


2010 ◽  
Vol 638-642 ◽  
pp. 261-266 ◽  
Author(s):  
Michal Kolar ◽  
Ketill Olav Pedersen ◽  
Sverre Gulbrandsen-Dahl ◽  
Thiemo Brüggemann ◽  
Knut Marthinsen

In order to investigate the effect of deformation on the aging response of Al-Mg-Si alloys, a series of tensile tests have been designed and carried out on two commercial aluminium alloys, i.e. AA6060 and AA6082. Extruded and solution heat treated specimens were pre-deformed 0%, 5%, and 10% (engineering strain), respectively followed by natural aging (NA). It was observed that the work-hardening rate increases with prolonged natural aging time and decreases with increasing pre-deformation prior to natural aging. The most significant effect of deformation was obtained for T4 temper i.e. after 1000 and 10000 minutes NA for the 6082 and 6060 alloy, respectively, when the amount of pre-deformation is 10%. A remarkable difference in work-hardening rate at the level of small plastic strains was observed compared to that of the material naturally aged for only 10 minutes. In addition to the tensile tests, transmission electron microscopy (TEM) has been used to characterize dislocation evolution for various combinations of pre-deformation and aging time.


2008 ◽  
Vol 584-586 ◽  
pp. 708-715 ◽  
Author(s):  
Erika Fernanda Prados ◽  
Vitor Luiz Sordi ◽  
Maurizio Ferrante

The present study is an assessment of the effects of precipitation heat treatments on tensile behaviour, work hardening (WH) characteristics and microstructural evolution of an Al-4%Cu alloy deformed by equal channel angular pressing (ECAP). Two ageing temperatures were employed (170 and 100oC) and their effect on strength and WH behaviour was compared with that exerted on the same alloy, but in two different initial conditions: quenched from solution temperature and slowly cooled before anneal. Grain and precipitate sizes of samples deformed by one and four ECAP passes and heat treated as described were measured employing transmission electron microscopy (TEM). It was concluded that the lower ageing temperature gives the best combination of strength and ductility, a high WH rate and, possibly, the smaller grain and precipitate sizes. The relative participation of the various hardening mechanisms to total strength was estimated from tensile tests and hardness measurements.


2019 ◽  
Vol 25 (3) ◽  
pp. 281-285
Author(s):  
Dhanashekar MANICKAM ◽  
Senthil Kumar VELUKKUDI SANTHANAM

Aluminium alloys are subjected to heat treatment to increase the strength and corrosion properties. This paper aims to study the effect of heat treatment on the compression behaviour of A356 alloy under quasi static condition and barreling effect. The various heat treatments are: (i) solution heat treatment of 1 h at 540 °C + natural aging 0 h + artificial aging at 180 °C up to 5.5 h, (ii) solution heat treatment of 3 h at 540 °C + natural aging for 20 h + artificial aging at 180 °C up to 5.5 h, and (iii) solution heat treatment of 6 h at 540 °C + natural aging for 20 h + artificial aging at 180 °C up to 5.5 h. Specially to understand the influence of artificial aging at every 0.5 h up to 5.5 h, the specimens were heat treated. From the results, solutionizing for 1 hr have a better compression strength irrespective of the artificial aging. Natural aging had decreased the ductility but increased the strength property. Artificial aging had a significant effect on the compressive strength and peak strength were obtained at 4 h irrespective of solutionizing heat treatment. Compressive strength increased by 33 % for 1 h of solutionizing and 4 h of artificial aged specimen when compared to non-heat treated alloy. Two mathematical relations discussed in literature were used for calculating the radius of the barreled surface followed by validation. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.20442


2010 ◽  
Vol 638-642 ◽  
pp. 401-406
Author(s):  
J.R. Calcaterra

Beta solution heat treatment is used to increase the fatigue crack growth resistance of Ti-6AL-4V. Unfortunately, the beta solution heat treatment is very sensitive to maximum temperature, time at temperature and cooling rate. In order to determine the effect of these parameters on mechanical properties, several different titanium billets and forgings were heat treated at various times and temperatures. The forgings had differing amounts of work, reflecting the potential for thermomechanical processing differences seen in a die forged component. Fracture toughness and tensile tests were conducted on the billets and forgings. In addition, sections of each work piece were excised and examined microscopically. The results from the study indicate there is a significant effect of heat treatment on thicker section components. In these cases, grains near the surface may grow large, while being barely transformed near the center. The change in microstructure has an effect on mechanical properties. Material with the larger grains tends to have worse ductility, while the fracture toughness properties of the material tend to decrease with grain size.


Author(s):  
J. R. Reed ◽  
D. J. Michel ◽  
P. R. Howell

The Al6Li3Cu (T2) phase, which exhibits five-fold or icosahedral symmetry, forms through solid state precipitation in dilute Al-Li-Cu alloys. Recent studies have reported that the T2 phase transforms either during TEM examination of thin foils or following ion-milling of thin foil specimens. Related studies have shown that T2 phase transforms to a microcrystalline array of the TB phase and a dilute aluminum solid solution during in-situ heating in the TEM. The purpose of this paper is to report results from an investigation of the influence of ion-milling on the stability of the T2 phase in dilute Al-Li-Cu alloy.The 3-mm diameter TEM disc specimens were prepared from a specially melted Al-2.5%Li-2.5%Cu alloy produced by conventional procedures. The TEM specimens were solution heat treated 1 h at 550°C and aged 1000 h at 190°C in air to develop the microstructure. The disc specimens were electropolished to achieve electron transparency using a 20:80 (vol. percent) nitric acid: methanol solution at -60°C.


2008 ◽  
Vol 8 (2) ◽  
pp. 722-727 ◽  
Author(s):  
Tae-hyun Nam ◽  
Cheol-am Yu ◽  
Jung-min Nam ◽  
Hyun-gon Kim ◽  
Yeon-wook Kim

Microstructures and deformation behaviour of Ti-45Ni-5Cu and Ti-46Ni-5Cu alloy ribbons prepared by melt spinning were investigated by transmission electron microscopy, thermal cycling tests under constant load and tensile tests. Spherical Ti2Ni particles coherent with the B2 parent phase were observed in the alloy ribbons when the melt spinning temperature was higher than 1773 K. Average size of Ti2Ni particles in the ribbons obtained at 1873 K was 8 nm, which was smaller than that (10 nm) in the ribbons obtained at 1773 K. Volume fraction of Ti2Ni phase in the ribbons obtained at 1873 K was 40%, which was larger than that (20%) in the ribbons obtained at 1773 K. The stress required at temperatures of Af + 10 K for the stress-induced martensitic transformation increased from 93 MPa to 229 MPa and apparent elastic modulus of the B2 parent phase increased from 56 GPa to 250 GPa with increasing the melt spinning temperature from 1673 K to 1873 K in Ti-45Ni-5Cu alloy ribbons. The critical stress for slip deformation of the ribbons increased by coherent Ti2Ni particles, and thus residual elongation did not occur even at 160 MPa, while considerable plastic deformation occurred at 60 MPa in the ribbons without Ti2Ni particles. Almost perfect superelastic recovery was found in the ribbons with coherent Ti2Ni particles, while only partial superelastic recovery was observed in the ribbons without coherent Ti2Ni particles.


2018 ◽  
Vol 165 ◽  
pp. 04006
Author(s):  
Angelika Brueckner-Foit ◽  
Inigo Bacaicoa ◽  
Martin Luetje ◽  
Marcel Wicke ◽  
Andreas Geisert ◽  
...  

The effect of the defect size and morphology on the fatigue damage evolution was analysed in a recycled Al-Si-Cu alloy by micro-computed tomography and scanning electron microscopy. Fatigue tests were performed and the different crack initiation scenarios were characterized and classified. The interaction between shrinkage and gas pores was the key crack initiation mechanism and the ß-Al5FeSi particles did not play any role in the crack initiation phase. However, crack path analysis indicated that there is a certain amount of crack advance by brittle fracture of the β-phase particles. This is in accordance with the findings of tensile tests in which the ductility depended strongly on the iron content.


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