| Magnesium and Magnesium alloys are used in automobile industry, space, aircraft, electronic, communication and defence industry fields as light-weight structural material, with its high specific strength, specific stiffness and hardness, good electromagnetic shielding characteristics and good machinability, recyalability and abundance. Magnesium alloys have a great of protential application value and prospect.The heat-resistant magnesium alloy ZC63 alloy is the Mg-Zn-Cu system. It is a potential fornew magnesium alloys, because it only contains Mg,Cu,Zn elements and low cost.The strength of the Mg-Zn alloy can also be enhanced by age strengthening, so the heat treatment can play a significant effective to improve the mechanical properties of the alloy. In recent years, the development of semi-solid forming technology are particularly prominent, the forming process and forming parts has some significant advantages, so the potential benefits of semi-solid magnesium alloy products is very large.This article selects the heat-resistant ZC63 magnesium alloy as the research object,firstly we can select as-cast alloys in its four different pouring temperatures to do the organize analysis and mechanical property tests, and found that the structure and mechanical properties of the ZC63 alloys in the different pouring temperatures are different. The organization of the as-cast ZC63 alloy at the pouring temperature of 715℃is tinier, the mechanical property is higher and its tensile strength can reach 204MPa; The organization of the as-cast ZC63 alloy at the pouring temperature of 685℃is bulky and irregular, its tensile strength is 186MPa.Then to research the heat treatment processes of the ZC63 alloy at the pouring temperature of 715℃, analyse and detect the changes of the organizations and mechanical properties. The compositions of the as-cast ZC63 alloy aremainlyα-Mg substrate, (Mg+CuMgZn) phase and Mg2Zn3. There has a new CuMgZn phase in the eutectic organizations after the T4 treatment, and precipitate a new strengthening phase CuZn after the T6 treatment. Finally we can found that the mechanical property of the ZC63 alloys after the T6 treatment (solid solution 445℃24h and ageing 160℃20h) is higher, its tensile strength can reach 240MPa. We take this T6 treatment to research the as-cast ZC63 alloy at the pouring temperature of 685℃, its mechanical property is better and the tensile strength can reach 242MPa. We can find that the the organizations and mechanical properties of the ZC63 alloys in the different pouring temperatures, which are treated by the same way are different, and the phase compositions are the same, but its distributions are different.We also want to research the evolution of partial re-melting organizations for the ZC63 alloys. First, take the the as-cast ZC63 alloy at the pouring temperatures of 685℃and 715℃to contrast the partial re-melting organizations in the different holding temperatures and the same holding time(30min). The organizations are different ,but the evolutions of the organizations are similar. Improving partial re-melting temperature can decreases the grain size, the partial re-melting organizations are more uniform and tinier when its in 610℃30min, they are more ideal.And then to research the evolution of partial re-melting organizations for the ZC63 alloys at the pouring temperature of 715℃, wich is in the same holding temperature and different holding time. The results show that extending the holding time, the organization will become more regular. The organization first melting separated then grew up, these two kinds of mechanism coexist in the whole evolution process of partial re-melting organizations. Meanwhile, we find that the composition and distribution of the phase for the partial re-melting ZC63 alloy are the same with the as-cast ZC63 magnesium alloy. |
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