本文選題：TZM合金板材　切入點：粉末冶金　出處：《西安建筑科技大學(xué)》2016年碩士論文

【摘要】：TZM(0.4%~0.55%Ti,0.06%~0.12%Zr,0.01%~0.04%C,余量為Mo)合金同時具有高熔點、高強度、強抗腐蝕性能和良好的高溫性能,是目前應(yīng)用最為廣泛的鉬合金之一。本文利用粉末冶金法制備了TZM及摻雜稀土元素鑭的La-TZM合金板材,La以硝酸鑭或La2O3粉末形式加入,C元素以硬脂酸的形式加入。通過金相觀察合金燒結(jié)坯與板材的組織,用Gleeble-3800熱模擬實驗機對合金燒結(jié)坯進(jìn)行熱模擬實驗,應(yīng)變速率分別為0.1s-1和0.01s-1,用高溫萬能拉伸機對合金板材進(jìn)行高溫拉伸實驗,用維氏硬度儀進(jìn)行了硬度測試,用SEM觀察微觀組織及斷口形貌。主要的研究結(jié)果如下:摻雜稀土元素La可以細(xì)化TZM合金的組織結(jié)構(gòu),起到第二相細(xì)晶強化的作用,液體摻雜硝酸鑭的TZM合金晶粒比固體摻雜氧化鑭的TZM合金晶粒小。在0.1 s-1和0.01s-1的應(yīng)變速率下,變形量為50%時,La-TZM合金的抗壓強度均隨著溫度的升高而降低,且其應(yīng)力-應(yīng)變曲線均為單峰值流變曲線,經(jīng)過壓縮,組織為纖維狀,未出現(xiàn)再結(jié)晶,說明試樣并未發(fā)生軟化現(xiàn)象,其開始再結(jié)晶溫度高于1200℃。在壓縮過程中,由于熱傳導(dǎo)和變形程度不均導(dǎo)致硬度存在明顯差異,變形中心區(qū)(區(qū)域Ⅲ)維氏硬度最高,未變形區(qū)(區(qū)域Ⅱ)次之,變形區(qū)邊緣(區(qū)域Ⅰ)最低。La2O3-TZM和La(NO3)3-TZM合金板材的高溫抗拉強度、高溫屈服強度及維氏硬度均隨著溫度的升高而降低,而La(NO3)3-TZM合金的高溫抗拉強度下降速率更快,即La(NO3)3-TZM合金溫度敏感性較高。軋制態(tài)合金板材隨溫度升高,材料韌性先升高后降低,1200℃時達(dá)到最大值。當(dāng)溫度小于1400℃時,La2O3-TZM與La(NO3)3-TZM合金板材的高溫斷裂方式主要為穿晶斷裂,當(dāng)溫度大于1400℃時,La2O3-TZM與La(NO3)3-TZM合金板材的斷裂方式主要為沿晶斷裂,故兩種La-TZM合金板材的斷裂方式在1400℃左右時由穿晶斷裂轉(zhuǎn)變?yōu)檠鼐嗔?即晶粒與晶界的等強溫度為1400℃。
[Abstract]:TZM0. 4 and 0. 55 Ti0. 06 and 0. 12. 12. The alloy has a high melting point, high strength, strong corrosion resistance and good high temperature properties, including 0.04C, with a margin of 0. 04C. It is one of the most widely used molybdenum alloys at present. In this paper, TZM and La-TZM alloy sheet doped with rare earth lanthanum were prepared by powder metallurgy method, and La was added in the form of lanthanum nitrate or La2O3 powder to add C element in the form of stearic acid. The microstructure of sintered billet and sheet metal was observed by metallography. The thermal simulation experiment of alloy sintered billet was carried out with Gleeble-3800 thermal simulation machine, the strain rates were 0.1s-1 and 0.01s-1.The high temperature tensile test of alloy sheet was carried out with high temperature universal drawing machine, and the hardness was tested by Vickers hardness tester. The microstructure and fracture morphology of TZM alloy were observed by SEM. The main results are as follows: doped rare earth element La can refine the microstructure of TZM alloy and play the role of second phase fine crystal strengthening. The grain size of TZM alloy doped with liquid lanthanum nitrate is smaller than that of TZM alloy doped with solid lanthanum oxide. At the strain rate of 0.1 s ~ (-1) and 0.01s-1, the compressive strength of La-TZM alloy decreases with the increase of temperature. The stress-strain curves are all single peak rheological curves. After compression, the microstructure is fibrous, and there is no recrystallization. It shows that the sample does not soften, and the recrystallization temperature is higher than 1200 鈩，

本文編號：1676836