高铝锌基合金的研究进展及应用

综述了近年来高铝锌基合金的研究进展及应用;阐述了铝含量对高铝锌基合金性能影响的研究;详述了通过合金化及变质处理、热处理、复合强化等方法和措施改善高铝锌基合金性能的研究;简要介绍了高铝锌基合金的应用现状。在此基础上,对高铝锌基合金的进一步发展提出了几点建议。

高铝锌基合金强化机制研究进展

文章综述了近年来高铝锌基合金的研究进展及应用,阐述了铝含量对高铝锌基合金性能影响的研究,论述了通过变质合金化处理、晶粒细化机制、熔体热速处理等方法和措施改善高铝锌基合金性能的研究现状,并在此基础上对高铝锌基合金的进一步发展提出了建议。

无钼镍高铬合金铸铁耐磨衬板的研制与应用

通过合金化及变质处理,洁净铁液,细化晶粒,改善高铬铸铁共晶碳化物的数量、形态和分布;严格工艺控制;优化热处理工艺等。研制生产出使用性能稳定,安全性高,耐磨性好的"新一代无钼镍高铬合金铸铁耐磨衬板"。与传统KmTBCr15Mo2Cu衬板相比,生产成本低,经济和社会效益明显。

Morphology modification of Mg_2Si by Sr addition in Mg-4%Si alloy

A modification of Mg2Si in the hypereutectic Mg-4%Si alloy（mass fraction） with Sr was investigated.Two types of Mg2Si in the alloys were found：polygonal primary Mg2Si and Chinese script type eutectic Mg2Si.Adding Al-10% Sr master alloy to the Mg-4%Si alloy clearly reduced the average size of primary Mg2Si and changed the morphology of eutectic Mg2Si from Chinese script type to polyhedral or fine fibre shape.The refinement of primary Mg2Si is mainly attributed to the heterogeneous nucleation mechanism induced by the Sr-rich particles.The modification of eutectic Mg2Si results from the dissolved Sr,which alters the preferred growth manner of the eutectic.

Effects of grain refining and modification on mechanical properties and microstructures of Al-7.5Si-4Cu cast alloy

Al-7.5Si-4Cu cast alloy melt modified by Al-5Ti-B, RE and Al-10Sr master alloys were poured in the chromite sand moulds, to investigate comparatively the effects of individual or combined additions of grain refiners and modifiers on the mechanical properties, microstructures, grain refining and modification, and intermetallic compounds of the alloy. The results show that the mechanical properties and the microstructures of Al-7.5Si-4Cu cast alloys are improved immensely by combining addition of 0.8%Al-5Ti-B, 0.1%RE and 0.1%Al-10Sr grain refiners and modifiers compared with the individual addition and cast conditions. For individual addition condition, addition of 0.8%Al-5Ti-B master alloy can obtain superior tensile strength, Brinell hardness and finer equiaxedα（Al） dendrites. The alloy with 0.1%RE master alloy shows the highest improvement in ductility because the rare earth can purify the molten metal and change the shape of intermetallic compounds. While the alloy with 0.1%Al-10Sr modifier shows only good improvement in yield strength, and the improvement of other performance is unsatisfactory. The Al-10Sr modifier has a significant metamorphism for the eutectic silicon, but will make the gas content in the aluminum alloy melt increase to form serious columnar grain structures. The effects of grain refining and modification on mean area and aspect ratio have the same conclusions obtained in the mechanical properties and the microstructures analyses.

Si phase morphology and mechanical properties of ZL107 Al alloy improved by La modification and heat treatment

The phase morphology evolution during the solid solution treatment and then artificial aging of the La-modified ZL107 Al alloy was studied. The results show that when the solid solution was held at 560 ℃ for 6 h, only partial Si phase dissolved into the matrix; however, the precipitation also occurred during the artificial aging process. The precipitation process in Al-Si alloys with or without La-modification was compared. After modification and heat treatment, the mechanical properties of the alloy were greatly enhanced, due to the modification and uniform distribution of Si phase.

Microstructure evolution and Al_3(Sc_(1-x)Zr_x) precipitates' kinetics in Al-Zn-Mg alloy during homogenization

The microstructure evolutions of two A1-Zn-Mg alloys, one of which was alloyed with Sc and Zr, and the kinetics of A13（SCl-xZrx） precipitates in the A1-Zn-Mg alloy during homogenization were investigated. Both alloys under as-cast condition with supersaturated, non-equilibrium T（Mg32（A1, Zn）49） phase and impurities phase were displayed. When the homogenization temperatures are below 350 ~C, Zn and Mg atoms precipitate from matrix; however, when the temperatures are above 400 ~C, T phase dissolves into matrix, enhancing solid-solution strengthening. Kinetics of A13（Scl.xZrx） precipitates was studied based on Jmat Pro software calculation and the difference values between the hardness of the two alloys in each homogenization condition. The calculations predict that the Sc and Zr solubilities in ct-A1 decline with the presence of Mg and Zn. Investigation of the difference values reveals that when the temperature is between 300 ~C and 350 ~C, the nucleation rate of A13（Sc1-xZrx） precipitates is the highest and the strengthening effect from A13（SCl_xZrx） precipitates is the best. After homogenization at 470℃ for 12 h, non-equilibrium T phase disappears, while impurity phase remains. The mean diameter of A13（Scl_xZrx） precipitates is around 18 urn. Ideas about better fulfilling the potentials of Sc and Zr were proposed at last.