Fabrication of Al-Cu-Mg Alloy Foams Using Mg as Thickener through Melt Route and Reinforcement of Cell Walls by Heat Treatment

Self Cite

We investigated pore formation in aluminum foams by controlling primary crystal morphology using three master alloys. The first one was a direct chill cast A2024 (Al-Cu-Mg) alloy (DC-cast alloy). The others were A2024 alloys prepared to possess fine spherical primary crystals. The second alloy was made by applying compressive strain through a Strain-Induced Melt-Activated process alloy (SIMA alloy). The third one was a slope-cast A2024 alloy (slope-cast alloy). Each alloy was heated to either 635 °C (fraction of solid fs = 20%) or 630 °C (fs = 40%). TiH2 powder was added to the alloys as a foaming agent upon heating them to a semi-solid state and they were stirred while being held in the furnace. Subsequently, A2024 alloy foams were obtained via water-cooling. The primary crystals of the DC-cast alloy were coarse and irregular before foaming. After foaming, the size of the primary crystals remained irregular, but also became spherical. The SIMA and slope-cast alloys possessed fine spherical primary crystals before and after foaming. In addition to average-sized pores (macro-pores), small pores were observed inside the cell walls (micro-pores) of each alloy. The formation of macro-pores did not depend on the formation of the primary crystals. Only in the DC-cast alloy did fine micro-pores exist within the primary crystals. The number of micro-pores in the SIMA and slope-cast alloys was one third of that in the DC-cast alloy.

Section: Introductionmentioning

confidence: 99%

Effect of Primary Crystals on Pore Morphology during Semi-Solid Foaming of A2024 Alloys

Kubo

Saito

Osaka

et al. 2019

Self Cite

“…These tendencies of the Melt-A2024 and Semi-A2024 samples were observed in almost all other samples. Moreover, by increasing the retaining time, the pores will expand and become coarser, and the porosity will also increase until the end of TiH 2 decomposition [5]. Moreover, it is thought that, with a change in foaming temperature, there will be no significant difference in the pores of Melt-A2024, unless the temperature falls below the liquidus line.…”

Section: Evaluation Of Compressive Propertiesmentioning

confidence: 99%

“…Therefore, using super duralumin A2024 alloy (Al-Cu-Mg) which is known as high strength lightweight material for base metal to increase strength and controlling the pore morphology to improve compressive properties has been researched. Fukui et al generated an oxide of Mg [4,5], which is contained in the A2024 alloy as a thickener instead of adding Ca.…”

Section: Introductionmentioning

confidence: 99%

Compressive Properties of A2024 Alloy Foam Fabricated through a Melt Route and a Semi-Solid Route

Kubo

Osaka

Saito

et al. 2019

Self Cite

A2024 alloy foams were fabricated by two methods. In the first method, the melt was thickened by Mg, which acts as an alloying element (melt route). In the second method, the melt was thickened by using primary crystals at a semi-solid temperature with a solid fraction of 20% (semi-solid route). A2024 alloy foams fabricated through the semi-solid route had coarse and uneven pores. This led to slightly brittle fracture of the foams, which resulted in larger energy absorption efficiency than that of the foams fabricated through the melt route. Moreover, A2024 alloy foams fabricated through the semi-solid route had a coarser grain size because of the coarse primary crystals. However, by preventing the decrease in the alloying element Mg, the θ/θ’ phase was suppressed. Additionally, by preventing the precipitation of the S′ phase, the amount of Guinier-Preston-Bagaryatsky (GPB) zone increased. This resulted in a larger plateau stress.

“…Table 1 shows the chemical composition of the A-242 alloy [12]. The automotive industry is constantly searching for innovation in its products, giving the opportunity to develop and innovate new materials which allow a better fuel efficiency and passenger safety [13]. Aluminium foams are an attractive alternative for this purpose because their properties are ideal for this purpose as its lightness and ability to absorb impact energy.…”

Section: Introductionmentioning

confidence: 99%

A-242 Aluminium Alloy Foams Manufacture from the Recycling of Beverage Cans

Rivera

Torres

Valdés

2019

This paper presents and discusses a methodology implemented to study the process of the preparation of aluminium alloy foams using the alloy A-242, beginning from the recycling of secondary aluminium obtained from beverage cans. The foams are prepared by a melting process by adding 0.50 wt.% calcium to the A-242 aluminium alloy with the aim to change its viscosity in the molten state. To obtain the foam, titanium hydride is added in different concentrations (0.50 wt.%, 0.75 wt.%, and 1.00 wt.%) and at different temperatures (923, 948 K, and 973 K) while the foaming time is kept constant at 30 s. For a set of experimental parameter values, aluminium alloy foams with the average relative density of 0.12 were obtained and had an 88.22% average porosity. In this way, it is possible to state that the preparation of aluminium alloy foams A-242 processed from the recycling of cans is possible, with characteristics and properties similar to those obtained using commercial-purity metals.