Effects of stirring parameters on the rheocast microstructure and mechanical properties of aluminum alloy ADC12

Abstract

In this study, effects of stirring time and stirring speed on the microstructure of semisolid rheocast (SSR) aluminum alloy ADC12 were examined. The research method was done by gravity casting using a metal mold. The aluminum ADC12 slurry is stirred by a mechanical stirrer (round rod stirrer) at 610OC with a variation of speed 0, 250, 300, 350 rpm for 0, 20, 40, 60 seconds. Furthermore, the aluminum slurry of ADC12 is poured on a metal mold with temperature 600OC. The microstructure characteristics were examined by direct observation using optical microscopy, secondary -Al phase dendrite arm spacing, shape factor, and Si eutectic phase were identified. The mechanical properties were investigated by hardness test and tensile test. A short period of stirring below the liquidus temperature to form a non-dendritic structure. The final morphology of the primary particles after a short period of stirring time has little impact as the stirring time increases. The optimal mechanical properties (hardness and tensile strength) were obtained at 20 seconds of stirring time and 300 rpm of stirring rate.

Effects of Stirring Time and Cooling Rate on the Rheocast Microstructure and Mechanical Properties of Magnesium Alloy MRI 230D

“…The interglobular structures, at the highest cooling rate, 6 mm sample (Figure 6A and B), became more refined and, at the lower cooling rate, 12 mm sample (Figure 6C and D) became coarser 8,21,22 .…”

“…Rheocasting is one of several methods to process metal alloys in a semisolid state. The main parameters of the process are stirring time, cooling rate, type of stirring, solid fraction and stirring speed and each of their variation directly affects the resulting microstructure 7,8 . The main spheroidization mechanism in the rheocasting process is the shear model, in which the dendritic arms are sheared and projected into the remaining liquid.…”

Analisis Struktur Mikro dan Kekerasan Paduan Aluminium ADC 12 Hasil Proses Pengecoran Semi Solid dengan Proses Perlakuan Panas

“…Pemanfaatan paduan aluminium juga diikuti oleh pengembangan dibidang teknologi prosesnya. Salah satu contoh teknologi prosesnya yaitu proses semi-solid forming rheocasting yang juga telah diteliti dalam penelitian sebelumnya [2][3][4][5][6][7]. Penelitian dilakukan guna meningkatkan kekerasan dan kekuatan bahan aluminium.…”

Pengaruh Kecepatan Pengadukan Proses Rheocasting terhadap Struktur Mikro dan Fluiditas Paduan Al-Cu

“…Umumnya ada dua metode untuk mengolah paduan Al-Cu proses tempa dan proses casting [10]. Namun biaya proses tempa sangat tinggi dibandingkan dengan proses pengecoran, dan sebaliknya proses pengecoran menghasilkan struktur dengan cacat coran seperti pori dan rongga penyusutan [11]. Dengan permasalah tersebut diperlukan proses pengecoran yang sesuai untuk meningkatkan fluiditas dan mereduksi cacat coran.…”