机械合金化法制备Ti-Zr-Ni-Cu储氢合金

使用行星式球磨机,用机械合金化法制备了Ti60Zr15Ni15Cu10储氢合金.采用X射线衍射仪XRD、示差扫描量热计DSC分析了球磨粉末的物相、晶粒尺寸的变化;采用扫描电子显微镜SEM、能谱EDS分析了机械合金化过程中粉末的形貌和成分;并对球磨粉末进行了P-C-T曲线测量.研究结果表明,粉末晶粒尺寸随球磨时间增加不断减小.球磨120 h粉末含有大量非晶相.粉末颗粒中有明显的冷焊合层状结构.随球磨时间增加,层状结构的层厚不断减小,颗粒中的元素分布趋于均匀,合金化过程中的冷焊合和断裂作用逐渐趋于平衡.合金的最大吸氢量物质的量为1.63%,纳米结构粉末的吸氢量高于非晶结构粉末.     

机械合金化制备Fe40Ni40Si5C15非晶合金

采用机械合金化方法制备了Fe-Ni-Si-C系的非晶态合金粉末,在球磨过程中对合金粉末进行取样,用XRD和DTA对不同球磨时间的Fe40Ni40Si5C15混合粉末进行了分析,发现合金粉末在球磨40 h开始部分非晶化,随球磨时间的增大晶粒尺寸减小。研究结果表明:在Fe-Ni-Si合金中加入C,可促进其形成非晶。通过机械合金化法,通过控制合理的球磨时间,在球磨70 h成功获得了Fe40Ni40Si5C15非晶粉末。     

机械合金化制备Fe-Co-C系非晶合金粉末

采用机械合金化方法制备出Fe—Co—C系的非晶态合金粉末。在球磨过程对合金粉末进行取样,通过X射线衍射的分析,发现合金粉末在球磨15～20h后开始部分非晶化,随球磨时间的增加晶粒尺寸减小。研究结果表明：在Fe—Co合金中加入C可促使其形成非晶;在一定的机械合金化条件下可获得Fe40Co40C20和Fe60Co20C20的非晶粉末,在球磨过程中,通过控制合理的球磨时间,可制备一系列晶粒尺寸的非晶材料。     

AlFeCrCoNi高熵合金的机械合金化法制备及退火行为研究

为了研究AlFeCrCoNi高熵合金的热处理工艺,文中采用机械合金化法制备了AlFeCrCoNi高熵合金,研究了球磨时间对Al、Fe、Cr、Co、Ni合金相变、晶粒尺寸、颗粒尺寸和球磨粉体形貌的影响,分析了球磨法制备的AlFeCrCoNi高熵合金的退火行为.研究结果表明:随着球磨时间的延长,晶粒尺寸逐渐减小,趋于稳定时其晶粒尺寸为34.球磨60h时,粉体颗粒形貌为球状,颗粒尺寸约为20μm.AlFeCrCoNi高熵合金在加热过程中分别在615.7℃、971.5℃和1 384.3℃出现三个吸热峰,前两个峰表明发生固态相变,1 384.3℃为高熵合金的熔点.     

球磨时间对机械合金化Mg-2Mn合金耐蚀性的影响

为研究球磨时间对机械合金化Mg-Mn合金耐蚀性能的影响,采用机械合金化及热压法制备Mn质量分数为2%,球磨时间分别为10 h和50 h的Mg-2Mn合金.对比研究不同球磨时间的Mg-2Mn合金的显微组织和在模拟体液中的腐蚀行为.球磨时间为50 h的Mg-2Mn合金晶粒细化程度明显高于球磨时间为10 h的Mg-2Mn合金.在模拟体液中动电位极化后,Mg-2Mn(10 h)合金腐蚀电位接近-1.28 V,Mg-2Mn(50 h)合金的腐蚀电位接近-0.4 V,对比发现Mg-2Mn(50 h)合金的腐蚀电位高,耐蚀性能好.在模拟体液浸泡实验时,不同球磨时间的Mg-2Mn合金的失重均较大,且随着浸泡时间延长,失重率下降,4 h后失重率下降明显,特别是Mg-2Mn(50 h)合金的失重率几乎不变.Mg-2Mn(10 h)合金浸泡10 h的平均腐蚀速度明显大于Mg-2Mn(50 h)合金,球磨时间为50 h的Mg-2Mn合金耐蚀性好于球磨时间为10 h的Mg-2Mn合金.     

高能球磨在复合材料制备中的应用

机械合金化（MA）技术作为一种制备新材料的有效方法已获得广泛的应用，利用该方法以获得常规条件下很难合成的具体独特性能的新型复合材料，高能球磨是机械合金化技术研究中的最新进展，利用高能球磨可在球磨过程中诱发低温化学反应，可制备性能优异的金属或陶瓷材料，介绍了利用高能球磨进行机械合金化的介面反应机理，固溶分解机理，自蔓延反应机理，高能球磨强度对材料制备的影响,机械合金化在金属基陶瓷复合材料和陶瓷基金属复合材料制备中的应用与发展。     

(Fe-Al)/Al_2O_3复合纳米粉体的机械球磨特性

采用机械球磨的方法制备(Fe Al)/Al2O3复合纳米粉体,通过对粉体的X衍射分析研究其机械球磨特性.结果表明:Al2O3阻碍球磨过程中的Fe、Al合金化,有利于粉末的纳米化和机械活化,并大幅提高出粉率.这对机械活化烧结FeAl基Al2O3弥散型块体复合纳米材料,提高机械球磨效率具有重要意义.     

球磨工艺对Y-Fe-Cr合金吸波性能影响

采用XRD、SEM和矢量网络分析仪分析相结合的方法研究球磨时间对Y-Fe-Cr合金微粉吸波性能的影响.结果表明:随着球磨时间从50 h不断增加,Y9Fe88Cr3吸波合金的吸收峰逐渐向低频移动;当球磨时间低于70 h时,合金扁平化及各向异性较好,其反射率较低,合金粉末吸波性能较好,在吸波涂层厚度为d=1.8 mm条件下,球磨时间为50 h和70 h的合金粉末的电磁波吸收峰峰值分别达到-14.7 dB和-14.4 dB,＜-10 dB的吸波带宽均达到7 GHz;当球磨时间达到80 h后,由于合金粉末颗粒碎化变细导致各向异性变差,其吸波性能变差,在吸波涂层厚度为d=1.8 mm条件下,合金粉末电磁波吸收峰峰值和＜-10 dB的吸波带宽分别为-12.5 dB和3.5 GHz,较球磨时间为70 h之前的合金粉末的吸波峰值和带宽减小了2 dB和3.5 GHz.研究结果为制备同类吸波合金微粉提供一定的理论依据.     

纳米晶W－Cu固溶体机械合金化研究

作者利用机械合金化制备了ＷｘＣｕ（１００－ｘ）（ｘ＝０～１００）合金．当ｘ＞８０时，获得的Ｗ－Ｃｕ合金是一种完全的Ｗ（Ｃｕ）固溶体．实验结果表明，球磨７０ｈ后，固溶体晶粒度为１０ｎｍ左右     

β-FeSi2热电材料的机械合金化制备

采用机械合金化法成功制备β-Fesi2热电材料.用X射线衍射法分析球磨机转速、球磨时间、退火工艺对混合粉末合金化进程的影响,采用热电性能检铡装置研究测试样品的热电性能.结果表明本实验条件下可完全生成β-Fesi2.     

Si和Al对机械合金化合成Ti3SiC2的影响

采用3Ti／Si／2C单质粉体为原料,进行机械合金化,以合成Ti3SiC2粉体。研究了Al和过量Si对机械合金化合成Ti3SiC2的影响。研究结果表明,机械合金化单质混合粉体,会诱发自蔓延反应。反应后产生大量坚硬的颗粒状产物。机械合金化3Ti／Si／2C粉体,会产生组成相为TiC、Ti3SiC2、TiSi2和Ti5Si3的粉体与颗粒产物。添过量Si并不会促进机械合金化反应合成Ti3SiC2。添适量Al可消除硅化物,明显促进反应合成Ti3SiC2。采用3Ti／Si／2C／0．15Al粉体作原料时,颗粒产物中Ti3SiC2含量最高,为92．8wt％;而采用3Ti／Si／2C／0．20Al粉体作原料时,粉体产物中Ti3SiC2含量最高,为61．9wt％。     

Formation mechanism of Ti5Si3 powder by mechanical alloying

The formation mechanism of stoichiometry Ti5Si3 by mechanical alloying (MA) from elemental powders has been investigated. The results of XRD and SEM analyses of the powder show that Ti5Si3 can be synthesized by MA in a planetary mill with two different formation mechanisms. Ti5Si3 was formed gradually with the mechanical collusion reaction (MCR) mechanism under a lower impact energy, and the Ti5Si3 was formed abruptly with the self-propagating high-temperature synthesis (SHS) formation mecha-nism under a higher impact energy.     

Si_3N_4-doped Zr_(50)Al_(15)Ni_(10)Cu_(25) glassy alloy by mechanical alloying and sintering process

Zr50Al15Ni10Cu25 amorphous powder was synthesized by mechanical alloying.The effect of Si3N4 addition on the crystallization behavior of the alloy during sintering process was studied.Thermal stability of the powders was performed by differential scanning calorimetry(DSC).The phase and microstructure of the powders and bulk specimens sintered were determined by X-ray diffractometry(XRD) and scanning electron microscopy(SEM).The results show that,introducing 0.05%(mass fraction) Si3N4 can enhance the crystallization activation energy of the Zr50Al15Ni10Cu25 amorphous powders,which indicates that Si3N4 addition has hindrance effect on forming crystals from Zr50Al15Ni10Cu25 amorphous powder.However,0.10% Si3N4 results in the decrease of the crystallization activation energy,which makes its crystallization process easy to occur.     

Al2O3对3Ti/Si/2C体系自蔓延高温合成Ti3SiC2的影响

以3Ti/Si/2C粉体为原料,通过自蔓延高温合成技术合成了Ti3SiC2材料。研究了Al2O3助剂对自蔓延高温合成Ti3SiC2的影响。研究结果表明,3Ti/Si/2C粉体会发生自蔓延反应,产物的组成相为TiC、Ti3SiC2和Ti5Si3,产物中Ti3SiC2含量约为23%。添加适量的细粒度Al2O3可显著促进反应合成Ti3SiC2,3Ti/Si/2C/0.1Al2O3原料反应后得到的产物中Ti3SiC2含量达64%。     

Fabrication of Fe-6 .Swt%Si Bulk by Spark Plasma Sintering

Fe-6.5 wt % Si composite compact was fobricated by spark plasma sintering (SPS) . Mechanical alloying( MA )was used to prepare Fe-Si composite powders. The composite powders were sintered by SPS at elevsated temperature from 500℃ to 700℃ . The experimental results indicate that the non-equilibrium state of composite Fe-Si is preserved in the compact. The density of the bulk rises with the increasing temperature and there is no diffusion of silicon and iron in the interface.     

Synthesis of high pure Ti3AlC2 and Ti2AlC powders from TiH2 powders as Ti source by tube furnace

Titanium aluminum carbide (Ti₃AlC₂ and Ti₂AlC) powders were synthesized from TiH₂ powders instead of Ti powders as Ti source by a tube furnace under argon atmosphere without preliminary dehydrogenation. 95 wt% pure Ti₃AlC₂ powders were synthesized from TiH₂/1.1Al/2TiC at 1 450 °C for 120 min. High-purity Ti₂AlC powders were also prepared from 3TiH₂/1.5Al/C and 2TiH₂/1.5Al/TiC powders at 1 400 °C for 120 min. The as-synthesized samples were porous and easy to be ground into powders. Sn or Si additives in starting materials increased the purity of synthesized Ti₃AlC₂ obviously and expanded the temperature range for the synthesis of Ti₃AlC₂. With Si or Sn as additives, high pure Ti₃AlC₂ was synthesized at 1 200 °C for 60 min from TiH₂/x Si/Al/2TiC and TiH₂/x Sn/Al/2TiC (x = 0.1, 0.2), respectively.     

反应物配比对液相合成Al2O3-SiO2-CaF2系玻璃粉体特性的影响

选用AlCl3、Na2SiO3、CaCl2和NaF作为初始反应物,采用液相沉淀法合成了Al2O3-SiO2-CaF2系玻璃粉体;通过XRD、EDAX和TEM等,分析了反应物配比对液相合成Al2O3-SiO2-CaF2系玻璃粉体特性的影响.结果表明,反应物配比对粉体的形貌、尺寸、结晶状态及所含的化学元素均无影响,而对元素的相对含量有明显的影响.各粉体均含有不同比例的O、F、Al、Si、Ca元素,且均为非晶态的近球形纳米颗粒,粒子直径大约在30~70 nm范围.     

纳米氧化铝颗粒增强铜-碳基复合材料的磨损性能

用MA技术制备了C体积分数为10%的Cu-C固溶体粉体,用溶胶-凝胶(sol-gel)烧结技术制备了平均尺寸为12 nm的γ-Al2O3颗粒和用SPS方法制备了纳米Al2O3颗粒增强Cu-C固溶体基复合材料。采用X射线衍射仪对MA粉体、干凝胶和煅烧粉体进行了物相分析;通过JSM-5500LV型扫描电镜对磨损表面形貌进行观察分析并分析其磨损机制;使用MG-2000型高温摩擦磨损试验机对制备的复合材料进行了干摩擦实验并测定其磨损量。结果表明:纳米氧化铝颗粒体积分数及磨损载荷对复合材料摩擦磨损特性有显著影响,纳米氧化铝的体积分数从0%增加到2%,Cu基复合材料的磨损量从6.2 mg降到2.1 mg。     

Comparative study of β-Si3N4 powders prepared by SHS sintered by spark plasma sintering and hot pressing

β-Si3N4 powders prepared by self-propagating high-temperature synthesis (SHS) with additions of Y2O3 and Al2O3 were sintered by spark plasma sintering (SPS). The densification, microstructure, and mechanical properties of Si3N4 ceramics prepared using this method were compared with those obtained by hot pressing process. Well densified Si3N4 ceramics with finer and homogeneous microstructure and better mechanical properties were obtained in the case of the SPS technique at 200℃ lower than that of hot pressing. The microhardness is 15.72 GPa, the bending strength is 716.46 MPa, and the fracture toughness is 7.03 MPa.m1/2.     

离子束增强沉积Al-N共掺杂ZnO薄膜的制备

用Al2O3粉体与ZnO粉体均匀混合,压制成溅射靶。在Si和SiO2/Si衬底上,用离子束增强沉积(IBED)方法对沉积 膜作Ar+/N+注入,制备Al-N共掺杂氧化锌薄膜(ANZO)。在氮气氛中作适当的退火,可以方便地获得取向单一、结构致 密、性能良好的共掺杂ZnO薄膜。探索用IBED方法在Si和SiO2衬底上制备优质掺杂薄膜的可能性。初步研究了ANZO共掺 杂薄膜的结构、电学和光学性能。