本文關(guān)鍵詞：Pt-Ti-X（Zr、Hf）微合金組織和力學(xué)性能研究　出處：《云南大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： Pt-Ti-X(Zr、Hf)微合金 冷軋 熱處理 顯微組織 力學(xué)性能

【摘要】：鉑合金具有極好的耐高溫、抗腐蝕、抗氧化、催化性能,賤金屬不可替代性,使得鉑材料廣泛應(yīng)用于各行業(yè)。但是高純度的鉑室溫強(qiáng)度低,嚴(yán)重限制了其廣泛的應(yīng)用,因此本論文期望通過添加微量的Ti、Zr、Hf使鉑微合金化,并結(jié)合相應(yīng)的處理工藝以提高鉑基微合金室溫力學(xué)性能。 本論文通過真空電弧熔煉制備了三種成分的Pt-Ti-X(Zr、Hf)微合金,即Pt-0.7Ti、 Pt-0.5Ti-0.2Zr、 Pt-0.5Ti-0.2Hfo通過金相顯微組織觀察、X射線衍射分析、透射電鏡觀察等手段研究了Pt-Ti-X (Zr、 Hf)微合金軋制、熱處理(固溶、時(shí)效、退火)后的組織變化規(guī)律,通過硬度測試,室溫拉伸力學(xué)性能測試手段研究了微合金在不同狀態(tài)下的力學(xué)性能。研究表明： (1)微量的Ti、Zr、Hf元素對Pt的固溶強(qiáng)化效果顯著。微合金Pt-0.5Ti-0.2Zr的硬度值達(dá)到147HVo2,是鑄態(tài)純Pt的2.5倍；微合金Pt-0.7Ti硬度值也大概提高為鑄態(tài)純Pt的兩倍,其值為118HV0.2;微合金Pt-0.5Ti-0.2Hf的固溶處理后硬度達(dá)到99HVo.2。在合金成分總量都是0.7wt.%的情況下,Ti-Zr對Pt固溶強(qiáng)化效果最顯著,而且單一元素Ti的固溶強(qiáng)化效果又比Ti-Hf二元元素的強(qiáng)。 (2)對Pt-Ti-X (Zr、Hf)微合金經(jīng)不同時(shí)效條件時(shí)效處理后,時(shí)效強(qiáng)化效果并不顯著。 (3)對Pt-Ti-X (Zr、Hf)微合金進(jìn)行多道次連續(xù)室溫軋制至最大變形量97%,加工性能優(yōu)異,而且加工硬化效果突出。固溶+冷軋和時(shí)效+冷軋的Pt-0.7Ti微合金硬度較固溶態(tài)、時(shí)效態(tài)分別提高了81%和79%,Pt-0.5Ti-0.2Zr微合金的分別提高67%和60%,Pt-0.5Ti-0.2Hf微合金的分別提高129%和117%；其中硬度值最高的是時(shí)效+冷軋后的Pt-0.5Ti-0.2Z撇合金,可達(dá)到253HVo.2。 (4)對軋制后微合金在500℃以下退火1h,硬度未發(fā)生明顯變化,合金組織幾乎保持加工態(tài)組織,還未開始再結(jié)晶；升高退火溫度至700℃時(shí),三種微合金的硬度值都只下降了20%-25%,并且微合金內(nèi)部組織都未完成完全再結(jié)晶；在800℃退火1h后,三種微合金的硬度仍是純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+冷軋后的158HVo.2，，時(shí)效+冷軋狀態(tài)的三種微合金和固溶+冷軋態(tài)的Pt-0.7Ti微合金都已完全再結(jié)晶,但是固溶+冷軋的Pt-0.5Ti-0.2Zr和Pt-0.5Ti-0.2Hf微合金組織還未完全再結(jié)晶；與純鉑相比再結(jié)晶溫度提高200℃以上。 (5)三種成分微合金材料的抗拉強(qiáng)度(σb)均得到大幅度提高。其中固溶+冷軋的Pt-0.5Ti-0.2Zr微合金獲得最高抗拉強(qiáng)度(σb)為740MPa,約是鑄態(tài)純Pt軋制后的2.2倍；在800℃退火1h后,三種微合金的抗拉強(qiáng)度仍是鑄態(tài)純Pt(119MPa)的2.4-3.4倍,其中最大抗拉強(qiáng)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+軋制后的29%。 綜上所述,微合金化、固溶強(qiáng)化、加工硬化能顯著改善鉑的力學(xué)性能,而且微量合金元素不僅對Pt材料的退火軟化有顯著地抑制作用,還能使微合金退火后具有較好的力學(xué)性能,這在擴(kuò)展鉑的實(shí)際應(yīng)用中極具潛在價(jià)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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