A novel sloping plate with wavelike surface was used to prepare semisolid alloy. Semisolid billets and slurries have been prepared by cooling or preheating the sloping plate. During preparation of the semisolid alloy by the proposed process, seed crystals derive from burst nucleation and breaking of dendrite and the coaction causes fine spherical microstructure formation. Casting temperature, sloping plate length, degree of cooling sloping angle are the main factors influencing the microstructure. Under current experimental conditions, in order to prepare good quality semisolid billets, proper casting temperature ranges of 660–690℃ for Al–3 wt-%Mg alloy and 660–680℃ for Al–6Si–2Mg (wt-%) alloy are suggested. The reasonable technological conditions for preparing Al–6Si–2Mg (wt-%) slurry are also proposed: the sloping plate preheating temperature is 300℃, and the casting temperature is 680℃. The optimum conditions for preparing semisolid billet of 1Cr–18Ni–9Ti stainless steel were obtained: the sloping plate length is 640 mm, and the casting temperature is 1600℃.

A novel testing machine for a continuous semisolid extending extrusion process (CSEP) has been designed and used to produce AA2017 alloy flat bar. Fine and homogeneous grains of AA2017 slurries with rosette structures were obtained at suitable casting temperatures. During preparation of semisolid AA2017 alloy by the proposed process, rosette grain formation was observed during the application of the large force provided by the rough roll. By controlling casting temperature, AA2017 products were produced with fine surfaces and rectangular transections of 14×25 mm. A casting temperature range of 710–750℃ was suggested. The microstructure of the product is fine and even with striped appearance and is composed mainly of h and a phases. The fracture strength of AA2017 product produced by the semisolid extending extrusion process is improved by 100 MPa, and elongation by 29%.

A vibrating wavelike sloping plate process (VWSP) was proposed. Heat and solute transformations, nucleation mechanism and grain growth as well as microstructure evolution were investigated. It is shown that the sloping plate can provide strong undercooling, and a large quantity of heterogonous nuclei appear on the sloping plate surface,wavelike flowand vibration can enable heterogonous nucleus to escape off the plate, which lead to nucleus multiplication. Moreover, wavelike flow and vibration improve solute diffusion coefficient and cause uniform solute and temperature field, which lead to eruptive nucleation. Grain growth has two typical ways, direct globular growth and dendritic growth. Under relative uniform temperature and solute fields, some grains can keep stable growth surface, go on growing with the round surface and finally maintain their globular structure. However, there are always some grains that grow along a certain preferred direction, but under wavelike flow and vibration their dendritic arms break and transform into near spherical structure. During the casting process, microstructural evolution from globular/dendritic structure to globular/equiaxed structure and to globular structure was observed.

Abstract: A self-designed setup of modified sloping cooling/shearing process was made to prepare the semisolid Al-3wt%Mg alloy. A three-dimensional simulation model was established for the analysis of preparing the semisolid Al-3wt%Mg alloy. Through simulation and experiment, it is shown that the sloping angle of the plate greatly affects temperature and velocity distributions, and the temperature and velocity of the alloy at the exit of the sloping plate increase with the increase of the sloping angle. The alloy temperature decreases linearly from the pouring mouth to the exit. The alloy temperature at the exit increases obviously with the increase of pouring temperature. To prepare the semisolid Al-3wt%Mg alloy with good quality, the sloping angle θ=45° is reasonable, and the pouring temperature is suggested to be designed above 650-660℃ but under 700℃.

研究了波浪型倾斜板振动参数对Al-6Si-2Mg合金凝固组织的影响，结果表明：倾斜板的倾角和长度影响合金在斜板表面的流动剪切强度和剪切时间，从而影响合金的组织，当浇注温度为660-690℃时，随着浇注温度的降低，合金晶粒细化和球化，平均晶粒直径为40μm，晶粒平均圆度值为2.5；浇注温度低于660℃时，晶粒有粗化和枝晶化的趋势，倾斜板的振动作用使表面形成的晶核离开表面进入熔体中，有效地减少了晶粒之间的粘连，解决了结壳问题，提高了形核率，细化了组织；随着倾斜板振动频率的提高，晶粒的平均圆度先降低后提高，振动频率为50-60 Hz出现最小值，倾斜板的波浪形表面对流动的金属具有搅拌作用，增大了熔体内部的剪切作用，使晶粒更加细小圆整。

通过对镁合金铸锭后显微组织的观察，结合SEM 能谱分析，研究了Ca,Mn 元素对镁合金组织的影响。研究发现，Mg-2.0Mn 的显微组织是由基体组织（α-Mg） 和点状析出的组织（α-Mn） 组成；Mg-0.5Ca 的显微组织是由（α-Mg） 基体组织和非平衡结晶形成的Mg2Ca 相组成Ca,Mn 对镁合金的组织均有细化作用，当同时加入Ca,Mn 合金元素时，镁合金的显微组织会更加细小，晶粒趋于均匀圆整，同时第二相颗粒减少其原因是:Ca 提高了Mn 与镁合金的润湿性，提高了Mn 的溶解与扩散能力，温度降低Mn 原子从合金中析出，为合金凝固提供了大量的晶核。

采用自行设计的波浪型倾斜板，在斜板冷却条件下制备了组织和触变性能优良的半固态合金坯料。而在斜板加热条件下制备出了组织优良的半固态合金浆料。在采用波浪型的倾斜板制备半固态合金过程中，在熔体爆发形核与枝晶破碎的共同作用下，形成了细小球形的半固态合金组织，浇注温度、冷却强度、斜板倾角和斜板表面材质是影响半固态合金组织的主要因素。得出了本试验条件下制备AIMg3合金半固态坯料的浇注温度范围为660～690℃制备AJSi6Mg2合金半固态坯料的浇注温度范围为600～680℃；制备AlSi6 Mg2半固态合金浆料的合理工艺条件为：斜板预热温度为300℃时，合金浇注温度为680℃。

采用新型倾斜板技术，通过半固态铸造制备过共晶Al-20Si合金材料，对Si相的尺寸与分布进行了研究。结果表明，新型倾斜板半固态铸造技术可以制备性能优良的Al-20Si合金，对初晶Si组织有很大的改善。在本试验条件下，倾角α=45°，倾斜板长度L=300mm，浇注温度t=630℃，倾斜板在室温条件下可获得细小均匀的初晶Si组织。

利用自制的实验装置对倾斜式剪切冷却技术制备1Cr 18Ni9Ti；不锈钢半固态合金进行了研究·倾斜式剪切冷却技术使熔融1Cr 18Ni9Ti不锈钢合金在剪切冷却作用下形成组织优良的半固态材料；在冷却板的冷却作用与重力的剪切作用下1Cr 18Ni9Ti；不锈钢半固态合金逐渐由树枝晶演化为细小的球形晶；倾角、冷却板长度、冷却板表面性质对合金组织具有重要影响；在倾角为45°，冷却板长度为650mm，冷却板采用紫铜材质的条件下可制备出细小球形的1Cr 18Ni9Ti；不锈钢半固态材料。

In this paper, a novel near-net-shape forming process, continuous semisolid extrusion process (CSEP) of AZ31 alloy was proposed, and the dynamical solidication behaviors and metal flow during the process were firstly investigated. During casting AZ31 alloy by this process, non-uniform microstructure distributions and non-equilibrium solidification region near the roll surface were found in the roll-shoe gap. Microstructural evolution from dendrite to rosette and spherical grains was observed during the casting by CSEP. Casting temperature, roll-shoe gap width and cooling ability have great effect on casting process and metal flow, so these factors should be carefully controlled, a proper casting temperature of 710-750℃ is suggested. The white α phases were strongly stretched during the processing, and the remnant liquids are correspondingly distributes along the solid phase boundaries and also show stripped lines.