A study on the subgrain superplasticity of extruded Al-Al3Ni eutectic alloy

Abstract

A directionally solidified Al-Al 3 Ni eutectic alloy was extruded to obtain micron-size subgrains with [111] fiber texture. The extrusion temperature was varied to have different distributions of the Al 3 Ni eutectic particles. Choosing the fiber axis as the loading axis, the tensile test results at 500 ЊC indicate that the elongation is concave downward and strain-rate dependent. Reducing the number of intragranular particles increases the maximum elongation as well as the strain rate of maximum elongation. With the particles residing only intergranularly in the as-extruded state, the maximum elongation, which occurs under the initial strain rate of 6.3 ϫ 10 Ϫ3 s Ϫ1 , is about 300 pct. This subgrain superplasticity is associated with low strain-rate sensitivity but high resistance against strain softening. The fiber texture is always retained, and the microstructure reveals slip of long parallel dislocations. If intragranular particles are also present in the as-extruded state, the occurrence of dislocation tangling and dynamic recovery will give rise to early onset of strain softening and inferior ductility.

Microstructural evolution in the superplastic-like deformation of Al-Al3Ni eutectic alloy with [111] fiber texture

“…Choosing the tensile direction paralcles are during this superplastic-like deformation. To clarify lel to the fiber axis and setting the testing temperature at these questions, details of our recent microstructure study 500 ЊC, we have found in our previous studies [6,7] that superwill be reported in the following. plastic-like behavior of extruded Al-Al 3 Ni eutectic alloy can take place if the Al 3 Ni eutectic particles in the as-extruded state are residing only intergranularly (i.e., at the sub-bound-II.…”

“…However, the final TEM 300 pct has been reported. [4][5][6][7] This total elongation is signifimicrostructure of the test material with superplastic-like cant in superplastic forming since the elongation required behavior reveals that some of the intergranular particles are in related engineering designs rarely exceeds 300 pct. [8] no longer intergranular.…”

“…Also, for the material deformed under its strain-rate condition of maximum elongation, the m values The Al-Al 3 Ni eutectic alloy used in this study is the same as that used in our previous studies. [6,7] It contains 11 vol as a function of strain have an average value of only about 0.25. [7] The value of strain-rate sensitivity is far below the pct Al 3 Ni particles and has the composition of 6.08 wt pct Ni, 0.2 wt pct Fe, 0.01 wt pct Mg, and 0.05 wt pct Si.…”

“…[6,7] It contains 11 vol as a function of strain have an average value of only about 0.25. [7] The value of strain-rate sensitivity is far below the pct Al 3 Ni particles and has the composition of 6.08 wt pct Ni, 0.2 wt pct Fe, 0.01 wt pct Mg, and 0.05 wt pct Si. For typical value of Ն0.4 for conventional superplasticity.…”

Alignment of primary Al3Ni phases in hypereutectic Al-Ni alloys with various compositions under high magnetic fields

“…With the development and the advance of superconducting magnet technologies, the application of a high magnetic field during the solidification process of metal materials to achieve aligned microstructure has been recognized as one of the useful technologies in materials processing [8][9][10][11] . Al-Ni alloys with non-eutectic compositions normally contain a wide range of volume percent eutectic which can meet higher technical demands on material properties and have been an important branch of research on functionally graded materials processing [12][13][14][15] . Studies on the mechanical properties of fiber-reinforced composite suggested that for Al-Ni alloys with an aligned-Al 3 Ni structure, their tensile and fatigue properties were remarkably improved in the direction along which the Al 3 Ni phases were aligned [16] .…”