發(fā)布時(shí)間：2018-06-25 20:01

  本文選題：TiAl基復(fù)合材料 + 陶瓷顆粒��； 參考：《濟(jì)南大學(xué)》2017年碩士論文

【摘要】：隨著車輛的高速化發(fā)展,當(dāng)今汽車普遍使用的鑄鐵制動(dòng)盤已經(jīng)滿足不了對(duì)安全性和節(jié)約能源的要求。其主要存在兩個(gè)大問題:一是密度大占據(jù)了制動(dòng)系統(tǒng)的大部分重量,二是鑄鐵材料的高溫工作性能不好、抗熱衰退性差。而TiAl基復(fù)合材料具有密度小、強(qiáng)度高、高溫工作性能好等特點(diǎn),如果將其用作汽車制動(dòng)盤材料來(lái)代替普通的鑄鐵將對(duì)汽車行業(yè)的發(fā)展具有重要意義。本文針對(duì)汽車制動(dòng)盤的性能要求對(duì)TiAl基復(fù)合材料進(jìn)行了基體成分的設(shè)計(jì)以及耐磨成分的設(shè)計(jì)。選取了Ti-60Al-2Cr-2Nb-1B做為基體,添加TiC和Al2O3陶瓷顆粒作為耐磨成分。然后采用真空熱壓燒結(jié)技術(shù)制備出性能優(yōu)良的TiAl基復(fù)合材料試樣。分別對(duì)復(fù)合材料試樣的物理力學(xué)性能、摩擦學(xué)性能進(jìn)行了研究。研究結(jié)果表明:隨著TiC和Al2O3添加量的增加,TiAl基復(fù)合材料相對(duì)密度逐漸減小,硬度先增大后減小;TiAl基復(fù)合材料抗彎強(qiáng)度隨著TiC添加量的增加先增大后減小,并且當(dāng)TiC添加量為12%時(shí)其抗彎強(qiáng)度最優(yōu);而隨著Al2O3添加量增加復(fù)合材料的抗彎強(qiáng)度逐漸減小。又對(duì)TiAl基復(fù)合材料分別進(jìn)行了干摩擦磨損、水潤(rùn)摩擦磨損、高溫摩擦磨損實(shí)驗(yàn)。研究結(jié)果表明:干摩擦磨損下,TiAl基復(fù)合材料摩擦系數(shù)隨著TiC和Al203添加量的增加先增大后減小。而磨損率隨著TiC和Al203添加量的增加開始呈減小趨勢(shì),但是當(dāng)添加量增加到一定量時(shí),磨損率反而又增大了,并且當(dāng)TiC和Al203添加量分別為12%和14%時(shí),復(fù)合材料的磨損率值最小。復(fù)合材料的摩擦系數(shù)隨著實(shí)驗(yàn)轉(zhuǎn)速的升高先增大后減小,磨損率隨著實(shí)驗(yàn)轉(zhuǎn)速的升高而逐漸增大。其中TiC添加量為12%的TiAl基復(fù)合材料的摩擦系數(shù)更加穩(wěn)定;水潤(rùn)摩擦磨損下,TiAl基復(fù)合材料的摩擦系數(shù)和磨損率相對(duì)于干摩擦磨損均有所降低,但是整體摩擦系數(shù)值仍能保持在0.3左右。并且TiC添加量為12%時(shí),TiAl基復(fù)合材料的磨損率值達(dá)到最低;在高溫摩擦磨損下,TiAl基復(fù)合材料的摩擦系數(shù)隨著溫度的升高而降低,TiC添加量為12%的復(fù)合材料磨損率在溫度小于300℃時(shí)緩慢變化,大于300℃時(shí)急劇增大。而Al203添加量為14%的復(fù)合材料磨損率在溫度小于400℃時(shí)緩慢變化,大于400℃時(shí)急劇增大。所以TiC添加量為12%的TiAl基復(fù)合材料的摩擦系數(shù)和磨損率的抗熱衰退性能更加優(yōu)異。利用ABAQUS對(duì)TiC添加量為12%的TiAl基復(fù)合材料制動(dòng)盤分別在緊急制動(dòng)工況和持續(xù)制動(dòng)工況進(jìn)行了仿真分析。研究結(jié)果表明:緊急制動(dòng)工況下時(shí),TiAl基復(fù)合材料制動(dòng)盤的最大溫度達(dá)到154.2℃,最大應(yīng)力達(dá)到88.94MPa。復(fù)合材料制動(dòng)盤的最大溫度和最大應(yīng)力都出現(xiàn)在制動(dòng)中期,溫度和應(yīng)力都經(jīng)歷了開始升高然后小幅度降低的過程;持續(xù)制動(dòng)工況下,復(fù)合材料制動(dòng)盤的最大溫度達(dá)到166.3℃,最大應(yīng)力達(dá)到138.9MPa。制動(dòng)溫度和應(yīng)力開始呈上升趨勢(shì)而后保持一個(gè)穩(wěn)定數(shù)值;兩種制動(dòng)工況下,TiAl基復(fù)合材料制動(dòng)盤的徑向溫度梯度和應(yīng)力梯度均大于周向。
[Abstract]:With the development of high speed vehicle, the cast iron brake disc which is widely used in automobile nowadays can not meet the requirements of safety and energy saving. There are two major problems: one is that the density occupies most of the weight of the braking system, the other is the poor high temperature working performance of cast iron and the poor resistance to thermal degradation. Tial matrix composites have the characteristics of low density, high strength and good high temperature working performance. It will be of great significance to the development of automobile industry if it is used as brake disc material instead of ordinary cast iron. In this paper, the matrix composition and wear resistance of tial matrix composites are designed according to the performance requirements of automobile brake discs. Ti-60Al-2Cr-2Nb-1B was chosen as matrix and tic and Al _ 2O _ 3 ceramic particles as wear resistant components. The tial matrix composites with excellent properties were prepared by vacuum hot pressing sintering. The physical and mechanical properties and tribological properties of the composites were studied. The results show that the relative density of tial matrix composites decreases with the increase of tic and Al _ 2O _ 3 content, and the flexural strength of TiAl-based composites increases first and then decreases with the increase of tic content. The flexural strength of the composite decreases with the increase of Al _ 2O _ 3 content, and the flexural strength of the composite decreases with the increase of tic content of 12. The experiments of dry friction and wear, wet friction and wear, high temperature friction and wear of tial matrix composites were also carried out. The results show that the friction coefficient of tial matrix composites increases firstly and then decreases with the increase of tic and Al203 content under dry friction and wear. However, the wear rate decreases with the increase of tic and Al203 content, but the wear rate increases with the increase of tic and Al203 content, and the wear rate is the lowest when tic and Al203 content are 12% and 14% respectively. The friction coefficient of the composites increases first and then decreases with the increase of the experimental speed, and the wear rate increases gradually with the increase of the experimental speed. The friction coefficient of tial matrix composites with tic content of 12% is more stable, and the friction coefficient and wear rate of tial matrix composites are lower than those of dry friction and wear under wet friction and wear. But the overall friction coefficient can still be kept around 0.3. The wear rate of tial matrix composites is the lowest when tic content is 12. Under high temperature friction and wear, the friction coefficient of TiAl-based composites decreases with the increase of temperature, and the wear rate of the composites with 12% tic content changes slowly when the temperature is less than 300 鈩，

本文編號(hào)：2067306