【作者】 邹茂华；

【导师】 刘昌明；

【作者基本信息】 重庆大学 ， 材料学， 2003， 硕士

【摘要】 本研究的目的是对ZL112Y铝合金用高频感应加热方法进行二次重熔，在半固态下压铸成形JH70型摩托车发电机支架。 采用高频感应加热装置和温度测定装置，在实验室里研究了ZL112Y压铸铝合金坯料高频感应加热二次重熔合适的半固态重熔温度、加热功率和速度，以及这些工艺参数对坯料的触变性能和微观组织的影响。实验结果表明：1)该合金合理的半固态二次重熔温度为570℃-571℃；2)在优化的感应加热工艺条件下，半固态重熔坯料内部的温差在0℃-1℃；3)半固态重熔过程使原始料坯中的α枝晶组织变成球团状和节杆状组织，满足了半固态触变成型的要求。 采用实验室所获得的二次重熔工艺在中国嘉陵集团重庆九方铸造有限责任公司生产现场成功地压铸成形了JH70型摩托车发电机支架半固态零件。在压铸零件的过程中，找寻合适的压铸工艺参数，以及模具内浇口设计，对成形铸件进行了组织观察、性能测定与分析；研究了压铸工艺参数对半固态成形零件成形性能的影响以及热处理对铝合金零件组织和力学性能的影响；基本上获得了在实际生产条件下压铸出合格的半固态零件的合理的工艺路线。 将压铸出的半固态零件与液态压铸零件以及二者热处理后零件制作成拉伸试样，对拉伸试样测定强度、延伸率，对它们的力学性能进行比较，同时测定它们的布氏硬度与洛氏硬度，观察微观组织，研究了ZL112Y压铸铝合金在半固态高压铸造成形过程中，不同阶段的试样中合金的组织演变过程。实验观察了原始料坯，压铸机压室内的冲头料坯以及压铸模内的内浇口和半固态压铸零件中不同部位的固相α组织的形貌。 通过分析与比较发现：半固态加工零件最大平均抗拉强度为170.50MPa，比液态加工零件平均抗拉强度值155.29MPa大9.79％：同时，最大的抗拉强度值(非平均值)为209.90MPa，是半固态成形后零件热处理所获得的数据，该值远远高于半固态未热处理的最高值185.39MPa，液态成形的最高值172.62MPa和液态成形热处理的最高值112.85MPa(非平均值)。由此表明，如果工艺控制较好，半固态成形比液态成形方式具有优越性：半固态加工零件的组织致密，力学性能高于液态加工的零件，经热处理后，零件的性能有得到提高的趋势。而液态压铸的零件不能进行热处理，热处理后材料的力学性能显著下降。从对组织和性能的测试分析表明：如果半固态压铸工艺得到进一步优化，零件的力学性能可以进一步提高，半固态成形后热处理的作用将会进一步发挥。更多还原

【Abstract】 The task of the research is to reheat ZL112Y aluminum alloy in the process of the high-frequency heating and to form a component of kickstand of generator of the type of JH70 motorcycle in semi-solid die casting processing.With a high-frequency induce heating equipment and a device for temperature measuring, reasonable semi-solid processing parameters, an appropriate semi-solid remelting temperature, heating power and speed, of ZL112Y aluminum alloy in the process of the high-frequency reheating and effects of these parameters on thixotropic behaviors of billets and microstructures of the alloy were searched. Results of the experiment show that, 1) proper semi-solid remelting temperatures of the alloy is in the range of 570℃-571℃; 2) in the condition of optimized reheating processing, the temperature deviation in a billet is O℃-1℃; 3) dendritical colonies of a phase in original billet changed into isolated grains with forms of nodules and granule, which may satisfy the need of semi-solid thixoforming forming in theory.The component was successfully formed in practice in semi-solid die casting processing by the semi-solid processing parameters obtained in laboratory at the locale of the factory of Chongqing JiuFang casting limited liability Company of JiaLing group.During the semi-solid die casting processing, appropriate semi-solid casting parameters and the sizes of ingate area were researched ,also, the microstructures and mechanical properties of the component in semi-solid die casting processing were investigated .And effects of casting parameters on the performances of the component in semi-solid die casting processing and heat treatment on microstructures and mechanical properties of components made of A1 alloy were observed. A reasonable processing for an eligible semi-solid component in practice was basically obtained.The strength and relative elongation of the specimens were measured, which were obtained from the components formed by semi-solid die casting and liquid die casting and these components with heat treatment, and the mechanical properties of the specimens were compared with each other. Further more, the Brinell hardness and Rockwell hardness of the specimens were measured. Meanwhile, Structural evolutions of ZL112Y aluminum alloy in procedures of semi-solid die casting were investigated.The structures of solid a phase of original billet, pierce block in the chamber of die-casting machine, ingate block in die-casting mould and specimens atdifferent locations in a semi-solid die casting component were observed.Results of observation and analyses show that: the maximum average value of tensile strength of the components formed by semi-solid die casting, 170.50MPa, is 9.79% greater than 155.29MPa, which is the average value of tensile strength of the components formed by liquid die casting; at the same time, 209.90MPa is the maximum(not average) value of tensile strength of the components formed by semi-solid die casting with heat treatment, which is much greater than 185.39MPa-the maximum value of the components formed by semi-solid die casting without heat treatment and 172.62MPa 梩he maximum value of the components formed by liquid die casting and 112.85MPa-the maximum value of the components formed by liquid die casting with heat treatment. Results show that semi-solid metal forming is superior to liquid metal forming if the parameters of the processing are well controlled: it can get the parts of higher integrity with superior mechanical properties, and there is a trend that the properties of the parts formed by semi-solid die casting with heat treatment are greater than that without heat treatment .While the part formed by liquid die casting can not be heat treated for its mechanical properties will be sharply reduced after heat treatment. Results of observing and analyzing the structures and mechanical properties of the specimens show that the mechanical properties will be enhanced if further optimizing the processing of semi-solid die casting can be carried out an更多还原