The Investigation Of Preparation Of AlCuFe Quasicrystalline And Enhancing ZL101 With AlCuFe And SiC Separately

The casting of Al-Si alloy has several good qualities, such as dense, wear-resisting, anti-fatigue, because of its good casting liquidity, but there is large primary α-Al inside itself, leading to generate the eutectic Si that is fragmented organization and influences the flowing of solution, which seriously affects the comprehensive performance and machinability of this type of alloy. Therefore, it is difficult to be widely applied in aerospace, automotive and other industries.Firstly, the conventional casting method was used to prepare Al（63+x）Cu_25-xFe₁₂（x = 0, 1） quasicrystal intermediate alloy, followed by appropriate heat treatment process, prompting the alloy in icosahedral quasicrystal phase composition tending to be single, then analyzing the difference of structures and properties between the two quasicrystal components and with the help of first-principles method, we have approximated the standard QC structure using its approximant phase, and the relevant properties of this quasicrystal structure were analyzed further after successful geometry optimization. Secondly, quasicrystalline that is single component was made of reinforced particles, thereby strengthening ZL101 alloy, comparing with SiC as the reinforcing phase. The mechanical properties, microstructure and XRD of the two type of material were analyzed.The results of test as follow: as-cast Al（63+x）Cu_25-xFe₁₂（x=0,1） quasicrystal intermediate alloy mainly includes four phases: primary-precipitated λ-phase, icosahedral quasicrystal I phase, β-phase（τ-phase） and other trace phases, respectively. After proper heat treatment, XRD diffraction peak of icosahedral quasicrystal phase increased significantly, yet its approximants reduced dramatically, quasicrystalline phases tending to be single. According to the analysis, no matter what kind of situation, such as microstructure and XRD analysis, these two components of quasicrystalline have no significantly difference. Then using the powder of quasicrystalline which has been ball milling（under 200 mesh, 100-200 mesh, large particles） strengthen ZL101 alloy. Comparing these analyses shows that after adding reinforcing phases primary a-Al that is inside ZL101 will be reduced in particle size, which plays a major role in grain refinment. In addition, eutectic Si which is sheet or stript shape is interrupted and its partical size become smaller, even uniformly distributed into the interior of the grain because of the quasicrystalline particles. The quasicrystalline partical size that is between 100 mesh and 200 mesh can have a optimal effect on reinforcing. The tensile strength of Al63Cu25Fe12/ZL101 has been increased to 357.26 MPa, the elongation has been added to 10.16% and the hardness has been increased to 63.6HB.Meanwhile, using the results that we have got about Al63Cu25Fe12/ZL101 composites compared with SiC/ZL101 composites. Results show that comprehensive performance of Al63Cu25Fe12/ZL101 is higher than SiC/ZL101 composites. Tensile strength has been rising by 41.9%, elongation has been rising by 25.89% and hardness is rising by 5.1%. The most important quality-mobility is still the former better than the latter. Based on the comprehensive analysis of macro-fracture, micro-fracture of Al-Cu-Fe/ZL101 composites is quasi-cleavage fracture.