(SiCp+C)/MoSi2复合材料的组织结构及力学性能

通过热压烧结工艺制得了(SiCp+C)/MoSi2复合材料,测试分析了材料的组织结构、室温和高温力学性能.结果表明:(SiCp+C)/MoSi2复合材料主要由MoSi2(大量),α-SiCp(大量),Mo5 Si3(多量)和β-SiC(少量)组成,密度为5.12g/cm3,相对密度为91%;增强相的粒径＜30μm,体积分数为39%.其室温硬度、抗弯强度和断裂韧性分别为12.2 GPa,530MPa和7.2MPa·m1/2;材料在800℃的维氏硬度为8.0 GPa,1 200和1400℃的抗压强度分别为560MPa和160MPa.与非增强MoSi2相比,材料的各种力学性能都有大幅度的提高.     

碳对二硅化钼复合材料性能的影响

采用热压烧结工艺制得了2％C/MoSi_2(质量分数)复合材料,并测定了材料的显微组织和结构、室温和高温力学性能、耐磨性能以及电阻率。结果表明:C/MoSi_2复合材料由大量的MoSi_2,Mo_5Si_3和少量的β-SiC组成;其维氏硬度为1 060,抗弯强度为470 MPa,断裂韧性为5.12 MPa·m~(1/2);800℃的维氏硬度为750 Hv,1200℃的抗压强度为450MPa,1400℃的抗压强度为142MPa;在Al_2O_3和SiC磨盘上表现出优异的耐磨性能,材料的电阻率为34.9 μΩ·cm。与纯MoSi_2相比,C/MoSi_2复合材料在硬度、抗弯强度、断裂韧性、高温抗压强度、弹性模量和耐磨性能等方面都有较大的提高。     

原位生长SiC/MoSi_2复合材料的制备工艺及其力学性能

通过反应烧结成功地制得了in-situ SiC/MOSi_2复合材料,该复合材料的组织均匀致密,相对密度达97.8％,强化相SiC的粒径小于1μm,体积分数为19.8％.复合材料室温抗弯强度为542MPa,断裂韧性5.21MPa·m~(1/2),维氏硬度12.21 GPa;在1200℃和1400℃时的抗压强度为596MPa和175MPa,800℃时的维氏硬度为8.2 GPa.在Al_2O_3和SiC磨盘上表现出优异的耐磨性能。     

加压烧结工艺对碳纤维增强TiC复合材料力学性能的影响

采用真空加压烧结工艺制备了 2 0 % (体积分数 )短碳纤维增强TiC复合材料 (Cf/TiC) ,研究了加压烧结温度、烧结时间和烧结压力对力学性能的影响。烧结温度由 190 0℃提高到 2 10 0℃ ,复合材料的横向断裂强度和断裂韧度分别由 387MPa和 4 14MPa·m1/2 提高到 5 93MPa和 6 87MPa·m1/2 ,当烧结温度再提高到2 2 0 0℃ ,强度和韧性反而有所下降。加压压力由 2 0MPa提高到 35MPa时 ,横向断裂强度和断裂韧度分别由5 5 7MPa、6 41MPa·m1/2 提高到 6 0 2MPa和 6 92Mpa·m1/2 。当保温时间由 0 5h提高到 2h时 ,复合材料的横向断裂强度和断裂韧度分别由 5 6 8MPa、6 5 3MPa·m1/2 提高到 5 93MPa和 6 87MPa·m1/2 。Cf/TiC复合材料合适的烧结工艺是在 2 10 0℃、30MPa下烧结 1h ,所制备的材料的相对密度为 97 6 % ,弹性模量为 416GPa ,横向断裂强度为 5 93MPa ,断裂韧度为 6 87MPa·m     

制备工艺对B4C/TiC/Mo陶瓷复合材料力学性能的影响

采用热压法制备了10%(质量分数)TiC/4.7%(质量分数)Mo增强B4C基陶瓷,分析了烧结温度、保温时间和烧结压力对力学性能的影响.烧结温度由1 800℃提高到1 900℃时,复合材料的抗弯强度由590MPa提高到705MPa;当烧结温度升至1 950℃,强度反而下降;硬度和韧度随烧结温度升高而提高.在烧结温度为1 900℃压力为35MPa保温时间由15min提高到45min时,抗弯强度由600MPa提高到705MPa;进一步增加保温时间,抗弯强度随保温时间的增加而下降;硬度和韧度随保温时间延长而提高.烧结压力对复合材料力学性能的影响较小.当烧结参数为1 900℃、45min、35MPa,B4C/TiC/Mo陶瓷复合材料抗弯强度、硬度、断裂韧度、相对密度分别为705MPa、20.6GPa、3.82MPa·m1/2、98.2%.     

TiC含量对钨基材料性能的影响

用热压烧结法制备了TiC含量 (体积分数 )分别为 0、10 %、2 0 %、30 %和 40 %的五种钨基材料 (TiC/W )。材料的硬度及弹性模量随TiC含量的增加而增大 ,分别由W基体的 3 4GPa、313GPa ,提高到 40 %TiC/W的 11 2GPa和 392GPa。随TiC含量的增加 ,材料的室温横向断裂强度和断裂韧度呈上升趋势 ,均在 2 0 %TiC/W时达到峰值 ,分别为 845MPa和 10 1MPa·m1/ 2 。随TiC含量增加 ,材料的热膨胀系数和比热容都增加 ,而热扩散率和热导率则显著下降。材料的热扩散率和热导率分别由W基体的 0 6 2 9× 10 -4 m2 /s和 15 3W / (m·K) ,提高到 40 %TiC/W的 0 110× 10 -4 m2 /s和 2 7 9W/ (m·K)     

短Cf增强SiC基复合材料及制备压力和Cf含量对其性能的影响

采用先驱体浸渍裂解(PIP)法、联合液相硅漫渍(LSI)工艺和纤维干磨分散技术制备了纤维随机分布的、其体积分数ψ(Cf)分别为5%、10%和15%的短纤维增强SiC基复合材料,并研究了模压压力及纤维体积分数对该复合材料力学性能的影响.结果表明纤维增强SiC基复合材料的力学性能随其模压压力变化有所改变,最佳模压压力为20 MPa;随短纤维体积分数ψ(Cf)在一定范围内增加,复合材料的性能有所上升,当ψ(Cf)为15%时,该复合材料的断裂韧性、弯曲强度、弹性模量和显微硬度(HV25)分别为4.42 MPa·m1/2、170.1 MPa、149.6GPa和5191.     

反应热压法制备TiN-SiC复合陶瓷材料

以Ti,Si3N4,石墨和SiC粉体为原料,用反应热压法合成了TiN-SiC复合陶瓷材料,并对其显 微结构及力学性能进行了研究。结果表明:该复合材料的维氏硬度和断裂韧性分别为13.6 GPa 和6.89 MPa·m1/2,其增韧机制主要为裂纹偏转和裂纹分叉机制。     

孔隙率对 YSZ 涂层性能的影响

本文采用高能等离子喷涂方法制备了孔隙率为 14.03%~28.22% 的多孔 YSZ 涂层， 研究了喷涂工艺参数对 涂层孔隙率以及涂层基本性能的影响。 结果表明： 随孔隙率的增加， 涂层的硬度和结合强度整体呈现下降的趋势， 孔隙率 14.03% 时硬度为 92.4， 孔隙率 26.04% 时硬度降低到 84.2， 强度则由 9.62 MPa 降低到 5.03 MPa； 涂层在 1060 ℃下抗热震次数呈现先明显增加后降低的趋势， 当孔隙率为 26.04% 时， 涂层在 464 次水冷热震后保持完好， 涂层抗热震性能最优。     

WC-Al2O3复合材料热压烧结工艺的改进

材料致密度的高低和晶粒的大小直接影响材料的力学性能和使用性能。为了进一步提高WC-Al2O3复合材料的致密度和控制晶粒尺寸,利用改进的普通热压烧结工艺,即二阶段热压烧结工艺对WC-Al2O3复合材料进行烧结,研究确定最佳二阶段烧结工艺及其对复合材料微观组织和力学性能的影响。结果表明,WC-Al2O3复合材料的最佳二阶段热压烧结工艺为TSS3,即T1=1 600℃,T2=1 450℃,t2=6 h。在TSS3烧结制度下制备的WC-Al2O3复合材料,其致密度(TD)为99%,WC晶粒尺寸为2.38μm,维氏硬度为19.71 GPa,断裂韧性为12 MPa·m1/2,抗弯强度为1 285.03 MPa。与普通热压烧结制度下制备试样的力学性能相比,晶粒尺寸有所减小,致密度、硬度、断裂韧性和抗弯强度均有较明显提高。     

Chinalco Signed Framework Agreement for Strategic Cooperation with Harbin Municipal Government

正Last month,Chinalco signed framework agreement for strategic cooperation with Harbin Municipal Government in Harbin Xiong Weiping,Chairman of Chinalco,said that based on the strategic deployment to build world top-class mining company with the highest growth potential,Chinalco was now concentrating all efforts on making strategic transition and structural adjustment,strategic cooperation with the local governments where     

Jiangxi Promotes Jiangxi Copper Corporation To Become The World's Most Competitive Mining Company

<正>According to the latest info from Jiangxi Province State-owned Assets Supervision and Administration Commission,Jiangxi Copper Corporation was approved to become the first pilot enterprise for deepening reform.Contents of the pilot work is"Three Self"(self expansion,self decision-making,self     

Journal of Rare Earths Contents List of Vol.32(2014)

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Contributions to Baosteel Technical Research wanted

正Baosteel Technical Research,a quarterly journal,which is issued domestically and abroad,is run and sponsored by Baosteel Group Corporation.Baosteel Technical Research mainly reports the achievements in technological innovation,academic research,new product development and industrial equipment improvement by Baosteel.It will continue to follow up on hot topics and serve the company’s technological development and progress.Its readers include experts in     

Ministry of Industry and Information Technology: No Short Term Solution For Our Country’s Excess Nonferrous Metal Smelting Capacity

【正】According to the Ministry of Industry and Information Technology,the Ministry has released the 2013 Operation Report on China’s Industrial Communication Indu...     

Chinalco Signed Framework Agreement for Strategic Cooperation with Gansu Province

正Recently,Chinalco and Gansu Provincial People’s Government signed"Framework Agreement for Strategic Cooperation on Reform,Restructuring and Transition Development of Chinalco’s Electrolytic Aluminum Enterprises in Gansu",signifying that the strategic cooperation between Chinalco and Gansu Province had made new substantive progress.     

Unavoidable Economic Cycle:30% Of Nonferrous Metal Companies Were Involved In Restructuring

正Owing to continual downturn in real estate and bulk commodity markets,a number of traditional industries in China suffered unfavorable impact in performance.With the progressive disclosure of third quarter report,the no-pleasant-surprise performance of     

Baotou Rare Earth Became the World's Biggest High Performance Magnetic Material Base

正The High Performance Magnetic Material Phase II Project,an industry upgrading project implemented by Inner Mongolia Baotou IronSteel Rare Earth(Group)Hi-tech Co.,Ltd,recently basically finished equipment commissioning,signifying that the enterprise had developed the production capacity of15000 t/a Nd-Fe-B strip casting alloy and 5000t/a Nd-Fe-B magnet,thus becoming the world’s     

Introducing Two Central Enterprises to Integrate Rare Earth Industry,Shandong Rare Earth Group Breaks Surface

正With the signing of"Letter of intention for Propelling Integration of Shandong Rare Earth Enterprises"between Shandong Province Commission Of Economy and Informatization,China IronSteel Research Institute Group("China Steel Institute"),and China Rare MetalsRare Earth Co.,Ltd("China Rare Earth"),the"Shandong Rare Earth Group"jointly set up by the 3 units thus broke surface.On August 9,reporters of the China Economic Herald learned from Shandong Province     

Aluminium Production by Province or City in 2014

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