本文選題：機(jī)械合金化 + 非化學(xué)計(jì)量比碳化鈦　； 參考：《燕山大學(xué)》2015年碩士論文

【摘要】：以Ti粉和Ti C粉為初始原料,采用機(jī)械合金化(MA)法合成非化學(xué)計(jì)量比Ti CX(x=0.4、0.5、0.6),然后將其和VC按一定比例進(jìn)行配混,在高溫高壓條件下進(jìn)行燒結(jié),壓力保持恒定的5.0GPa,調(diào)整燒結(jié)溫度和保溫時(shí)間,研究燒結(jié)工藝參數(shù)以及非化學(xué)計(jì)量化合物Ti Cx中不同的C含量對(duì)燒結(jié)后試樣結(jié)構(gòu)和性能的影響。首先將Ti C0.4與VC進(jìn)行分層疊燒,在掃描電鏡下,借助于EDS技術(shù)分析二者界面附件各元素的分布,討論界面處各種元素原子的擴(kuò)散行為,由此判斷VC中的C原子是否可以擴(kuò)散進(jìn)入到Ti Cx的空位中;其次研究Ti C0.4和VC的混合粉體的燒結(jié),測(cè)定燒結(jié)體的維氏硬度和斷裂韌性,通過SEM觀察分析燒結(jié)體斷口形貌,獲得的最佳結(jié)合劑配方為Ti C0.4的體積分?jǐn)?shù)為70%,VC的體積分?jǐn)?shù)為30%,燒結(jié)溫度為1500℃,燒結(jié)樣品的維氏硬度為22.5GPa,斷裂韌性值為3.69MPa·m1/2;當(dāng)燒結(jié)溫度為1600℃時(shí),樣品出現(xiàn)過燒現(xiàn)象;再次研究Ti Cx中不同C含量,即x取不同值時(shí),以及保溫時(shí)間不同對(duì)Ti Cx/VC燒結(jié)體性能的影響。將燒結(jié)溫度選定在1450℃、1500℃、1550℃三個(gè)溫度,x分別為0.4、0.5、0.6時(shí),其高溫保溫時(shí)間分別為5min、10min、15min時(shí),測(cè)定Ti Cx/VC燒結(jié)體的硬度和斷裂韌性,對(duì)燒結(jié)后樣品進(jìn)行X射線衍射分析,確定其物相構(gòu)成;并觀察其斷口形貌,找到x值對(duì)燒結(jié)行為的影響以及燒結(jié)保溫時(shí)間對(duì)性能的影響。實(shí)驗(yàn)結(jié)果表明,Ti C0.5/VC燒結(jié)體在保溫15min,燒結(jié)溫度為1500℃時(shí),硬度值達(dá)到最大為21.13GPa,韌性值為3.87 MPa·m1/2,Ti C0.6/VC燒結(jié)體在保溫15min,燒結(jié)溫度為1400℃時(shí),硬度值最大,最大值22.24GPa,韌性值為3.73 MPa·m1/2。對(duì)于不同x值的Ti Cx/VC燒結(jié)體,隨著x值增大,樣品完全燒結(jié)所需要的保溫時(shí)間逐漸縮短。
[Abstract]:Using Ti powder and tic powder as initial raw materials, the non-stoichiometric ratio of Ti CXX XN 0.4U 0.5N 0.6 was synthesized by mechanical alloying (MA) method, and then mixed with VC in a certain proportion and sintered under high temperature and high pressure. The influence of sintering process parameters and different C content in nonstoichiometric compound TiCx on the structure and properties of the sintered samples was studied by adjusting sintering temperature and holding time with constant pressure of 5.0 GPA. Firstly, TiC0.4 and VC were laminated and superimposed. The distribution of elements in the interface between them was analyzed by means of EDS technique, and the diffusion behavior of various elements at the interface was discussed. It is concluded that the C atom in VC can diffuse into the vacancy of TiCx. Secondly, the sintering of the mixed powder of TiC0.4 and VC is studied, the Vickers hardness and fracture toughness of the sintered body are measured, and the fracture morphology of the sintered body is observed and analyzed by SEM. The optimum formulation of the binder is: the volume fraction of TiC0.4 is 70%, the volume fraction of VC is 30, the sintering temperature is 1500 鈩，

本文編號(hào)：1855291