【作者】 陈刚；

【导师】 张云鹏；

【作者基本信息】 西安理工大学 ， 材料科学与工程， 2010， 硕士

【摘要】 TZM合金(Titanium-Zirconium-Molybdenum Alloy)是钼基合金中广泛应用的一种高温合金,也是目前商业用途中一种重要的高温合金。该合金具有熔点高,强度大,弹性模量高,膨胀系数小,蒸气压低,导电导热性好,抗蚀性强以及高温力学性能良好等特点,因而其在诸多领域得以广泛应用。本文采用粉末冶金的方法制备了TZM合金板坯,并对细晶粒TZM合金板坯进行了大变形量轧制,最后对轧制后的TZM合金板进行了退火。在制备过程中,研究了元素Ti、Zr对烧结的影响,研究了TZM合金板坯的轧制形变能力、形变致密化机理和规律、强化机理和规律,研究了该工艺条件下材料的组织结构、性能变化规律以及轧制加工与后续热处理对材料组织结构与性能的影响。研究主要取得以下成果：(1)元素Ti、Zr以TiH2、ZrH2的形式加入,虽然略微降低了烧结钼坯的致密度,但是却细化了烧结钼坯中的晶粒。合金元素Ti和Zr一方面固溶到Mo基体中,另一方面生成(Mo,Ti,Zr,)xOy化合物存在于晶粒之间以及晶粒表面,净化了合金中的氧,对位错产生钉扎作用,从而有利于合金强度的提高。(2)与纯钼板的轧制工艺相比,TZM合金板的轧制工艺应适当提高其开坯温度、热轧终轧温度及温轧温度,热处理过程中提高退火温度。(3)变形温度、变形程度两个压力加工条件是对TZM合金板坯热轧变形强化的主要影响因素,而退火工艺参数也显著影响着轧制后TZM合金板的组织性能。选择合适的变形温度、道次压缩率、总压缩率,设计合理的退火工艺是研究要解决的关键问题。(4)对TZM合金板坯进行了大变形量轧制,用轧制提高材料的强度和延伸率,用最终热处理调节材料性能,使材料的晶粒拉长产生纤维化,材料内部晶界杂质偏析明显降低。研究了轧制变形量对材料性能的影响,发现轧制后材料的强度、延伸率随变形量的增大而显著提高。更多还原

【Abstract】 The TZM alloy (Titanium-Zirconium-Molybdenum Alloy) is present widely applicated as a kind of high-temperature alloy in Molybdenum alloys. And it possessed high melting-point, large strength, high elasticity modulus, little expansion coefficient, low vapor pressure, good electric conductivity and thermal conductivity, strong corrosion resistance as well as good high temperature mechanical properties.In this thesis, the TZM alloy plate was prepared by power metallurgy technology, and the fine-grained TZM alloy plate was deformed by a large compression ratio hot-rolling, finally the TZM alloy plate was annealing after hot-rolling. In the preparation process, the influences of Zirconium and Titanium elements on TZM alloy sintering were studied. Based on fine-grained TZM alloy plate, the densification was explored by hot-rolling. The capacity of hot-rolling densification, the mechanism of hot-rolling densification and laws of densification and the mechanism and laws of strengthening of fine-grained TZM alloy plate were studied. Microstructure, property and changes and the effect on microstructure and property by hot-rolling and follow-up of heat treatment were researched. The main results are as follows:(1) The element of Ti and Zr were added to TZM alloy as form of TiH2 and ZrH2, which reduced the density of sintered molybdenum slightly, but the grains of sintered molybdenum were refined. The results indicated that the alloyed element Zr and Ti, on the one hand were solved into the Mo matrix, on the other formed (Mo, Ti, Zr)xOy composite oxide particles with Mo and oxygen in the alloy, and existed in grains between internal and surface. This kind of dispersion phase absorbed the oxygen and fixed the dislocation in the TZM alloy, thus improved the strength of TZM alloy.(2) The TZM alloy plate compared with pure molybdenum plate of rolling technology, we should improve the temperature of breakdown rolling, finish thermo-rolling and tempreture rolling, and add annealing tempreture in heat treatment process. (3) The results showed that the deformation temperature and pressure were two of the main influential factors of processing conditions for TZM alloy plate by hot-rolling deformation, and the parameters of annealing technology also significantly affect the microstructure and property after the rolling. To choose the right deformation temperature, the compression ratio, the total compression ratio, design and reasonable parameters of annealing technology were the key issues.(4) The TZM alloy plate was deformed and densified by a large compression ratio rolling to increase the strength and elongation. The properties were regulated by heat treatment finally, so that grain was lengthened and fibrosised by rolling. Internal boundary impurities segregation decreased significantly. The effect on performance by the compression ratio of hot-rolling was studied. It showed that strength and elongation significantly increased with the increase of deformation after the hot-rolling.更多还原