Abstract
Aluminum alloys have been widely used in various engineering applications due to their excellent physical properties such as low density, high strength and good cutting capacity. In this paper, the semi-solid thixotropic extrusion forming process is proposed to produce aluminum alloy 6063 shells for mobile phones. The effects of the operating parameters on the equivalent stress distribution, velocity field, temperature field, and the load of the top mould were investigated through numerical simulations. Optimal parameters were identified from the simulation results. The experiment was then conducted at these optimal parameters. The macromorphology and microstructure results of the mobile phone shells produced from the experiment are presented and discussed. It was found that the optimal process parameters for preparing aluminum alloy 6063 shell by the semi-solid thixotropic extrusion process were a billet temperature of 630 °C, mould temperature of 400 °C, and top mould speed of 10 mm/s. It was found that the mobile phone shells fabricated under the optimal operating conditions were fully filled with a clear outline and a smooth surface. The solid grains in the microstructure were small, uniform and nearly spherical. The average grain size of the microstructure for the product was obtained as 76.92 μm and the average shape factor was found as 0.76.
Highlights
Al-Mg-Si-based wrought aluminium alloys are attractive materials applied in the computers, communication, and consumer electronics (3C) and automotive industries because of their excellent mechanical properties
The semi-solid thixotropic extrusion forming (SSTEF) process is one of the representative techniques used in semi-solid metal forming (SSMF) processes, which can be defined as a forming process where semi-solid billets with fine and spherical solid grains are extruded into final parts in a preheated mould [7]
The AZ91D magnesium alloy experiencing the deformation of repetitive upsetting-extrusion at 340 ◦C for three cycles was isothermally treated at 580 ◦C for 10 min, and semi-solid billets with an average grain size of 59.87 μm and a shape factor of 0.84 were successfully fabricated, which are suitable for investigating the constitutive behavior of a strain-induced melt activation (SIMA)-processed magnesium alloy
Summary
Al-Mg-Si-based wrought aluminium alloys are attractive materials applied in the computers, communication, and consumer electronics (3C) and automotive industries because of their excellent mechanical properties. The AZ91D magnesium alloy experiencing the deformation of repetitive upsetting-extrusion at 340 ◦C for three cycles was isothermally treated at 580 ◦C for 10 min, and semi-solid billets with an average grain size of 59.87 μm and a shape factor of 0.84 were successfully fabricated, which are suitable for investigating the constitutive behavior of a SIMA-processed magnesium alloy. It was found that semi-solid AZ91D magnesium billets with the average grain size of 5 um could be prepared by the SIMA process which includes equal channel angular extrusion and SSIT processes. Both the room temperature and high-temperature mechanical properties of the formed components were enhanced effectively. In Group II, the billet temperpartoucresiss osefttfhreommo62b5il–e63p5h°oCnewsithhetlhl eisminovueldsttiegmatpeedrabtyurGeroofu4p0s0 I°IC-IaVn. dInthGereoxutrpuIsIi,onthsepbeieldleot f te1m0 mpemra/tsu, rwehisilseeitnfrGomrou6p25I–I6I,3t5h◦eCmwoiuthldthteemmpoeuraldtutreemvpaerireastufrroemof 345000–◦4C50an°Cd twhiethextthreusbiiollnet stpeemepdeoraftu10remofm6/30s,°wC hainlde itnheGerxotruupsiIoInI, stpheeedmoofu1ld0 mte/ms.pInerGatruourepvIVar,itehseferoxtmrus3i5o0n–4sp5e0e◦dCis wchitahngtheed binilltehtetreamnpgeeroaftu5–re15omf 6m3/0s ◦uCndaenrdthtehebleaxntkruasnidonmsopueleddteomf p1e0ramtu/rse.s Ionf G63r0ou°Cp aIVnd, t4h0e0e°xCt,ruressipoenctsipveeelyd. is changed in the range of 5–15 mm/s under the blank and mould temperatures of 630 ◦C and 400 ◦C, respectively
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