The Preparation Of Al-Cu-Fe Quasicrystal And Its Application In ZL101Alloy

The Al-Si alloy is widely used in casting aluminum alloy, because its has good flowproperty, shrinkage of small, dense castings, good wear resistance and excellent castingperformance. However, when the alloy was obtained by conventional casting method, theprimary silicon is quite thick and big. It will reduce the mechanical properties of aluminumalloy. For the moment, we can change the morphology of Si phase in aluminum silicon alloyby adding the second phase into the Al-Si alloy. Al-Cu-Fe quasicrystal particles have someunique properties, such as high hardness, high wear resistance, and good wettability ofaluminum alloy matrix. So it is very suitable for the strengthening phase of the Al-Si alloy. Inthis paper, in order to improve the performance of Al-Si alloy, Al-Cu-Fe quasicrystal wasadded into ZL101alloy. This can can prepare high-performance aluminum matrix composites,on the other hand, it can also provide an experimental basis for the study of quasicrystal.In this paper, Al63Cu25Fe12and Al60Cu25Fe12Si3quasicrystal intermediate alloy wereprepared by conventional casting, and analyze its microstructure and phase composition. Andwe study the effect of heat treatment on the phase formation of quasicrystals. we selected abest Al-Cu-Fe quasicrystal composition as the strengthening of Al-Si alloy phase. In order toobtain the75-150m quasicrystal particles, the choice of quasicrystal particles will be milling.Then the quasicrystalline particles were added into ZL101, studied the influence of theamount of quasicrystals, pouring temperature and heat treatment on Microstructure andmechanical properties of composite materials.The tests show that the as cast Al63Cu25Fe12and Al60Cu25Fe12Si3quasicrystal intermediatealloy mainly produces four different phases in the solidification process: λ phase, I phase, βphase（τ phase）and other micro phase. After heat treatment, the β phase peak intensity issignificantly reduced, and compared with Al63Cu25Fe12,Most of the β phase of Al60Cu25Fe12Si3alloy transition for I phase, and othermiscellaneous phase is less, so choice the Al60Cu25Fe12Si3quasicrystal as a strengthening ofthe Al-Si alloy phase.After the Al60Cu25Fe12Si3quasicrystal particles were added into ZL101alloy, the size of primary-Al decrease in size, and its primary dendritic tapering, two spacing dendritebecomes small, the form began to change for the rosette. In addition, sheet or strip shapeeutectic Si is interrupted, the size becomes relatively small. With the increasing content ofquasicrystal,-Al and eutectic Si will further refine.The mass fraction of added quasicrystal is1%,2.5%and4%respectively. when in acertain temperature （680℃,700℃or720℃）, if increase the adding content, the tensilestrength, hardness and elongation has an obvious promotion. When pouring temperature is700℃, Al60Cu25Fe12Si3quasicrystal particles addition amount was4%, the compositematerials has the best performance. The tensile strength, hardness and elongation were245MPa,69.6HB and4.1%. Compared with ZL101, the performance were increased by34.6%,35.9%and28.1%respectively. And the fracture mode of the composite belongs to quasicleavage fracture.Heat treatment process for this article are: the solution of535℃±5℃/8h，after65℃water quenching and aging temperature is170±5℃, time of6h,8h and10h. The eutectic Sicompleted the fuse and granulation stage in the process of heat treatment, so aftet heattreatment, the morphology of eutectic Si is greatly improved, the majority of the eutectic Sihas granulation.In addition, the mechanical properties of the composites improved obviously after heattreatment. With the increase of aging time, the tensile strength and hardness increased, but itsplasticity decreased. When the aging temperature is10h, the tensile strength, hardness andelongation were302MPa,103.6HB and5.5%, compared with the as cast composites, wererespectively increased by23.3%,48.9%and34.1%.