金属玻璃凝固过程温度场检测及模拟分析

发布时间：2018-04-09 15:53

  本文选题：金属玻璃　切入点：温度场　出处：《沈阳工业大学》2017年硕士论文

【摘要】：不同于晶态合金的凝固过程,金属玻璃由于冷却速度快、熔体原子来不及扩散重排,凝固过程中不产生结晶现象。其整个凝固过程中没有潜热释放,凝固降温曲线中不出现平台。由于金属玻璃凝固过程中这种潜热消失的机制尚不明确,因此,有必要对金属玻璃的凝固规律进行探究。本文采用水冷淬火和铜模铸造两种方式制备了Zr_(41)Ti_(14)Ni_(10)Cu_(12.5)Be_(22.5)块体金属玻璃,利用EM9104C多路数据采集仪对其凝固过程进行了温度场数据采集。在所得温度数据的基础上,对合金与不同传热介质间的界面换热系数进行了推导计算,给出了液固界面推进速度在不同坐标系中的表达式。同时利用ProCAST数值模拟软件模拟了Zr_(41)Ti_(14)Ni_(10)Cu_(12.5)Be_(22.5)块体金属玻璃的铜模冷却凝固过程,并预测了最大理论制备直径。计算与模拟结果表明:水淬法制备直径为16mm的Zr_(41)Ti_(14)Ni_(10)Cu_(12.5)Be_(22.5)块体金属玻璃时,合金表面温度从920℃冷却至100℃需要的时间为26.5s,通过有限差分方程计算得到的合金与石英管间界面换热系数平均值约为1300W/(m2?K)。改用铜模浇铸制备Zr_(41)Ti_(14)Ni_(10)Cu_(12.5)Be_(22.5)块体金属玻璃时,合金与铜模间的界面换热系数随合金温度的升高而增大,但不是线性比例关系。直径8mm的Zr_(41)Ti_(14)Ni_(10)Cu_(12.5)Be_(22.5)块体金属玻璃冷却速度曲线模拟结果与实测值基本吻合。在浇注温度为840℃时,使用铜模可制备的Zr_(41)Ti_(14)Ni_(10)Cu_(12.5)Be_(22.5)块体金属玻璃最大理论直径尺寸约为125~130mm。水淬法制备金属玻璃在温度场测量方面存在较大局限性,对探究金属玻璃凝固过程的研究不适用。相比于晶化凝固方式,合金熔体按非晶方式凝固时,合金比热容在玻璃转变点附近存在着阶跃台阶,而潜热的消失与这种比热的变化有一定关联。
[Abstract]:Different from the solidification process of the crystalline alloy, due to the rapid cooling rate, the melt atoms do not have the diffusion and rearrangement, and the crystallization does not occur during the solidification process.There is no latent heat release in the whole solidification process, and no platform appears in the solidification cooling curve.Since the mechanism of the latent heat is not clear during the solidification of metallic glass, it is necessary to study the solidification law of metallic glass.In this paper, water quenching and copper mold casting are used to prepare ZrS / 41T / T / NiSZ / NiSZ / 10 / 10 / CuSZ / Cu / T bulk metallic glass. The temperature field data are collected by means of EM9104C multichannel data acquisition instrument for the solidification process of the bulk metal glass (12.5B / 22.5). The results are as follows: (1) in this paper, the solidification process is studied by means of EM9104C multichannel data acquisition.On the basis of the obtained temperature data, the interfacial heat transfer coefficient between alloy and different heat transfer media is derived and calculated, and the expression of the liquid solid interface advancing velocity in different coordinate systems is given.At the same time, the cooling solidification process of Zr _ S _ I _ (41) Titig _ (14) Nii _ (10) CuT _ (12. 5) Bei _ (22. 5) bulk metal glass was simulated by using the ProCAST numerical simulation software, and the maximum theoretical preparation diameter was predicted.The results of calculation and simulation show that the preparation of metal glass with a diameter of 16mm by water quenching method is 41 / 1 tititiun / Nitix / 10 / 10 / CuSZ / 12.5 / Bei / 22.5) bulk metallic glass.It takes 26.5s for the surface temperature of the alloy to be cooled from 920 鈩，

本文编号：1727103