Pt-Ti-X（Zr、Hf）微合金组织和力学性能研究

发布时间：2018-01-11 07:21

  本文关键词：Pt-Ti-X（Zr、Hf）微合金组织和力学性能研究　出处：《云南大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： Pt-Ti-X(Zr、Hf)微合金 冷轧 热处理 显微组织 力学性能

【摘要】：铂合金具有极好的耐高温、抗腐蚀、抗氧化、催化性能,贱金属不可替代性,使得铂材料广泛应用于各行业。但是高纯度的铂室温强度低,严重限制了其广泛的应用,因此本论文期望通过添加微量的Ti、Zr、Hf使铂微合金化,并结合相应的处理工艺以提高铂基微合金室温力学性能。 本论文通过真空电弧熔炼制备了三种成分的Pt-Ti-X(Zr、Hf)微合金,即Pt-0.7Ti、 Pt-0.5Ti-0.2Zr、 Pt-0.5Ti-0.2Hfo通过金相显微组织观察、X射线衍射分析、透射电镜观察等手段研究了Pt-Ti-X (Zr、 Hf)微合金轧制、热处理(固溶、时效、退火)后的组织变化规律,通过硬度测试,室温拉伸力学性能测试手段研究了微合金在不同状态下的力学性能。研究表明： (1)微量的Ti、Zr、Hf元素对Pt的固溶强化效果显著。微合金Pt-0.5Ti-0.2Zr的硬度值达到147HVo2,是铸态纯Pt的2.5倍；微合金Pt-0.7Ti硬度值也大概提高为铸态纯Pt的两倍,其值为118HV0.2;微合金Pt-0.5Ti-0.2Hf的固溶处理后硬度达到99HVo.2。在合金成分总量都是0.7wt.%的情况下,Ti-Zr对Pt固溶强化效果最显著,而且单一元素Ti的固溶强化效果又比Ti-Hf二元元素的强。 (2)对Pt-Ti-X (Zr、Hf)微合金经不同时效条件时效处理后,时效强化效果并不显著。 (3)对Pt-Ti-X (Zr、Hf)微合金进行多道次连续室温轧制至最大变形量97%,加工性能优异,而且加工硬化效果突出。固溶+冷轧和时效+冷轧的Pt-0.7Ti微合金硬度较固溶态、时效态分别提高了81%和79%,Pt-0.5Ti-0.2Zr微合金的分别提高67%和60%,Pt-0.5Ti-0.2Hf微合金的分别提高129%和117%；其中硬度值最高的是时效+冷轧后的Pt-0.5Ti-0.2Z撇合金,可达到253HVo.2。 (4)对轧制后微合金在500℃以下退火1h,硬度未发生明显变化,合金组织几乎保持加工态组织,还未开始再结晶；升高退火温度至700℃时,三种微合金的硬度值都只下降了20%-25%,并且微合金内部组织都未完成完全再结晶；在800℃退火1h后,三种微合金的硬度仍是纯Pt硬度(38HVo.2)的2.5-4.2倍,其中硬度最高的是Pt-0.5Ti-0.2Zr微合金固溶+冷轧后的158HVo.2，，时效+冷轧状态的三种微合金和固溶+冷轧态的Pt-0.7Ti微合金都已完全再结晶,但是固溶+冷轧的Pt-0.5Ti-0.2Zr和Pt-0.5Ti-0.2Hf微合金组织还未完全再结晶；与纯铂相比再结晶温度提高200℃以上。 (5)三种成分微合金材料的抗拉强度(σb)均得到大幅度提高。其中固溶+冷轧的Pt-0.5Ti-0.2Zr微合金获得最高抗拉强度(σb)为740MPa,约是铸态纯Pt轧制后的2.2倍；在800℃退火1h后,三种微合金的抗拉强度仍是铸态纯Pt(119MPa)的2.4-3.4倍,其中最大抗拉强度是Pt-0.5Ti-0.2Zr微合金的415MPa,延伸率最高的是微合金Pt-0.5Ti-0.2H涸溶+轧制后的29%。 综上所述,微合金化、固溶强化、加工硬化能显著改善铂的力学性能,而且微量合金元素不仅对Pt材料的退火软化有显著地抑制作用,还能使微合金退火后具有较好的力学性能,这在扩展铂的实际应用中极具潜在价值。
[Abstract]:Platinum alloys have excellent resistance to high temperature, corrosion resistance, oxidation resistance, catalytic performance, base metal irreplaceable, make platinum materials widely used in various industries, but the high purity of platinum at room temperature strength is low. Due to the serious limitation of its wide application, this paper hopes to improve the mechanical properties of platinum based microalloying at room temperature by adding a small amount of TiOZrHf, and combining with the corresponding treatment process in order to improve the mechanical properties of platinum based microalloys at room temperature. In this paper, three kinds of Pt-Ti-XnZrHf-based microalloys, Pt-0.7Ti, Pt-0.5Ti-0.2Zr, were prepared by vacuum arc melting. Pt-0.5Ti-0.2Hfo was used to study the rolling of Pt-Ti-X zirconium (HF) microalloys by means of X-ray diffraction and transmission electron microscopy. The microstructure changes after heat treatment (solution, aging and annealing) were studied by means of hardness test and tensile mechanical properties at room temperature. (1) the microamounts of TiOZrZrHf have a remarkable effect on the solution strengthening of Pt, and the hardness of the microalloy Pt-0.5Ti-0.2Zr is 147HVo2. It is 2.5 times as high as the as-cast pure Pt. The Pt-0.7Ti hardness of the microalloy is about twice as high as that of pure Pt, and its value is 118HV0.2. The hardness of microalloy Pt-0.5Ti-0.2Hf after solution treatment is 99HVo.2.When the total composition of the alloy is 0.7wt.%. The effect of Ti-Zr on Pt solution strengthening is the most obvious, and the solution strengthening effect of Ti is stronger than that of Ti-Hf binary element. (2) the aging strengthening effect of Pt-Ti-X Zirconium Hf) microalloy under different aging conditions is not significant. (3) the Pt-Ti-X Zirconium Hf) microalloy was rolled continuously at room temperature for many times until the maximum deformation was 97%, and the processing performance was excellent. The hardness of Pt-0.7Ti microalloy in solution cold rolling and aging cold rolling is higher than that in solid solution, and the aging state is increased by 81% and 79%, respectively. The Pt-0.5Ti-0.2Zr microalloys were increased by 67% and 60, respectively. The Pt-0.5Ti-0.2Hf microalloys were increased by 129% and 117, respectively. The highest hardness of the alloy is the aging cold rolled Pt-0.5Ti-0.2Z skim alloy, which can reach 253HVo.2. (4) the hardness of the microalloys annealed below 500 鈩

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