放电等离子烧结制备多孔镍催化材料

研究以球形雾化镍粉为原料通过放电等离子烧结(SPS)制备多孔镍块体催化材料的新工艺,用SEM、氮吸附和XRD分析制备的多孔镍块材的微观结构和相组成,并进一步研究多孔镍材对甲烷部分氧化法(POM)制取合成气反应的高流速催化性能。结果表明,采用SPS工艺可制备出孔隙率大于70%的纯净多孔镍材,850 ℃保温120 s制备的镍材可应用于流速达2.70 L/min的POM反应,经其催化的CH4转化率高于80%     

放电等离子烧结制备医用多孔锌镁合金的孔隙特征和力学行为（英文）

采用放电等离子烧结技术制备多孔Zn-Mg合金,探讨了Mg含量对多孔合金孔隙特征和力学性能的影响,并分析了多孔Zn-Mg合金的断裂失效机制。结果表明,在造孔剂(NaCl)体积分数固定前提下当Mg含量从5%增加至15%(质量分数),由于在去除造孔剂的过程中去合金化作用,孔隙率从40.3%提升至54.3%,表面开孔直径从289μm增加到384μm。力学测试结果表明,多孔Zn-Mg合金为一种弹脆性多孔材料;3种组分中多孔Zn-10Mg合金力学性能最好,其强度与弹性模量均能满足作为承受低载荷松质骨的需求。     

放电等离子烧结法制备二硼化钛多孔陶瓷

以二硼化钛微粉为原料，采用放电等离子烧结技术，通过控制烧结温度、保温时间、施加压力等工艺参数，成功的制备出具有高强度和高气孔率的二硼化钛多孔陶瓷。采用浸泡介质法，三点弯曲法测试了材料的气孔率，开口气孔率及强度；用扫描电镜对材料断口进行了观察。实验结果表明：在1300-1500℃的烧结温度下，获得了气孔率33％～45％，最大抗弯强度〉60MPa的二硼化钛多孔陶瓷。扫描电镜结果显示，二硼化钛颗粒间有明显的颈部烧结。     

放电等离子烧结Nd—Fe—B过程特征

研究了不同烧结温度下,放电等离子烧结的Nd-Fe-B永磁体在烧结过程中样品收缩量随温度的变化,讨论了提高样品密度的措施.放电等离子烧结的Nd-Fe-B永磁体晶粒细小且均匀,晶粒平均尺寸为3.8 μm,为一般传统粉末烧结制备Nd-Fe-B磁体晶粒尺寸的1/4.     

放电等离子烧结快速制备致密Ti-Al基合金

以Ti-47.5Al-2.5V-1.0Cr合金粉末为原料,研究了采用放电等离子烧结工艺制备Ti-Al基合金.研究表明,当烧结温度高于1100 ℃时,可制备出致密度高、组织均匀的Ti-Al基合金;烧结温度对合金的显微组织影响显著,在1100 ℃和1150 ℃烧结,得到由等轴γ晶粒与α2 γ片层束构成双态组织,在1200 ℃烧结时,得到全部由α2 γ片层束构成的全片层组织;当烧结温度为1100 ℃时,具有细小双态组织的合金具有较佳的室温力学性能,其抗压强度为3321 MPa,压缩率为35.2%.     

放电等离子烧结制备氧化锆陶瓷及其力学性能

以日本Tosoh纳米氧化锆粉体为原料,采用放电等离子烧结(SPS)技术及无压烧结技术制备了氧化锆纳米陶瓷。运用TEM﹑SEM﹑XRD等对粉体和块体进行分析,比较无压烧结及不同SPS烧结温度的样品显微结构及力学性能。结果表明:在试验范围内SPS烧结样品力学性能随烧结温度升高而升高,抗弯曲强度在1500℃时达到1483MPa,可切削性低于无压烧结组。利用放电等离子烧结技术可以明显提高ZrO2的力学性能,但并不能改善其可切削性能。     

放电等离子烧结制备超细WC基硬质合金

采用纳米碳化钒(V8C7)粉末作为晶粒抑制剂及放电等离子烧结(SPS)方式制备超细WC基硬质合金.X射线衍射结果表明:超细WC基硬质合金主要由WC和Co3C两相组成,随着温度的升高,WC的衍射峰逐渐向小角度偏移.扫描电镜结果表明:SPS和纳米V8C7粉末对超细WC基硬质合金的微观组织具有重要影响.SPS使超细WC基硬质合金在较低温度下(1200℃)实现致密化;纳米V8C7粉末可以有效抑制超细WC基硬质合金中WC的晶粒长大,1200℃时WC的晶粒尺寸约500 nm.力学性能结果表明:1200℃时超细WC基硬质合金具有较高的性能(相对密度99.5%,洛氏硬度93.2,断裂韧性12.5 MPa·m1/2).     

双晶WC硬质合金的 放电等离子烧结制备与性能研究

选用2种不同粒度的WC粉末按照一定的配比,采用SPS烧结制备出无粘结剂的双晶硬质合金样品,对样品的维氏硬度、断裂韧性、抗弯强度等力学性能进行测试,并用XRD和SEM对其物相组成和微观形貌进行分析。实验结果表明,在1 900℃,40 MPa烧结条件下,当超粗颗粒平均粒径为45.0μm时,双晶WC硬质合金的硬度、断裂韧性和抗弯强度达到最大值,分别为1 645 HV1,14.61 MPa·m~(1/2),653.0 MPa,综合力学性能最佳。     

WC-7Co硬质合金放电等离子烧结工艺

采用放电等离子烧结(spark plasma sintering,SPS)技术制取WC-7Co硬质合金。研究了烧结温度、烧结压力对烧结WC-7Co硬质合金力学性能的影响,探讨了最佳烧结热压比,分析了粉末烧结致密化过程和晶粒长大机制。结果表明,WC-7Co硬质合金在1150℃烧结时,随着压力的增加,烧结致密性呈现先增加后降低的变化趋势,在30 MPa时可获得最佳烧结致密性。在升温速率为100℃/min,保温时间为5 min,烧结温度为1150℃,热压比为38℃/MPa的工艺条件下,利用SPS技术可制备组织致密、综合力学性能良好的WC-7Co硬质合金。     

纳米WC-6%Co复合粉的放电等离子烧结研究

以水溶液化学法制备的WC-6%Co纳米复合粉体为原料,利用放电等离子烧结(spark plasma singtering,SPS)技术制备了超细硬质合金。研究了烧结温度对硬质合金显微组织和力学性能的影响,分析了纳米粉体烧结的致密化过程。结果表明:随着烧结温度的升高,烧结致密性、硬度和断裂韧性都呈现先增加后降低的变化趋势,在升温速度为100℃/min,烧结温度为1 250℃,保温时间5 min,压力为30 MPa的工艺条件下,利用SPS技术可制备综合力学性能良好的超细晶硬质合金,平均晶粒大小为420 nm,维氏硬度为1 969 HV30,断裂韧性为10.7 MPa·m~(1/2)。     

Microstructures and mechanical properties of TiAl alloy prepared by spark plasma sintering

A fine-grained TiAl alloy with a composition of Ti-47%Al(mole fraction) was prepared by double mechanical milling(DMM) and spark plasma sintering(SPS). The relationship among sintering temperature, microstructure and mechanical properties of Ti-47%Al alloy was studied by X-ray diffractometry(XRD), scanning electron microscopy(SEM) and mechanical testing. The results show that the morphology of double mechanical milling powder is regular with size of 20?40 μm. The main phase TiAl and few phases Ti₃Al and Ti₂Al were observed in the SPS bulk samples. For samples sintered at 1000 °C, the equiaxed crystal grain was achieved with size of 100?250 nm. The samples exhibited compressive and bending properties at room temperature with compressive strength of 2013 MPa, compression ratio of 4.6% and bending strength of 896 MPa. For samples sintered at 1100 °C, the size of equiaxed crystal grain was obviously increased. The SPS bulk samples exhibited uniform microstructures, with equiaxed TiAl phase and lamellar Ti₃Al phase were observed. The samples exhibited compressive and bending properties at room temperature with compressive strength of 1990 MPa, compression ratio of 6.0% and bending strength of 705 MPa. The micro-hardness of the SPS bulk samples sintered at 1000 °C is obviously higher than that of the samples sintered at 1100 °C. The compression fracture mode of the SPS TiAl alloy samples is intergranular fracture and the bending fracture mode of the SPS TiAl alloy samples is intergranular rupture and cleavage fracture.     

Microstructures of mechanically activated Ti-46at.%Al powders and spark plasma sintered ultrafine TiAl alloy

Powder of Ti-46at.%Al was synthesized through mechanical activation (MA) for different milling times, and the 16 h MAed powder was sintered by using a spark plasma sintering (SPS) process at different sintering temperatures. The XRD profiles showed that the MAed Ti-46at%Al powder for 12,16, and 20 h contained initial α-Ti and Al phases, and that the SPSed TiAl alloys contained the gamma TiAl and α2-Ti3Al phases. The TEM showed two different types of regions in the 16 h MAed Ti-46at.%Al powder. One type consisted of only Al with a grain size about 80 nm, and the other type a mixture of Al and Ti with a grain size of 30 nm. According to the optical micrographs of MA-SPSed samples, the alloys sintered at higher temperatures showed a coarser microstructure. In the case of the 1473 K sintering, typical duplex structures ((α2 γ) lamella and γ phases) with interlamellar spacings of 50-400 nm and the grain size either less man 100 nm, or 1000 nm were observed.     

Microstructures of mechanically activated Ti-46at.% Al powders and spark plasma sintered ultrafine TiAl alloy

Powder of Ti-46at.%Al was synthesized through mechanical activation (MA) for different milling times, and the 16 h MAed powder was sintered by using a spark plasma sintering (SPS) process at different sintering temperatures. The XRD profiles showed that the MAed Ti-46at%Al powder for 12,16, and 20 h contained initial α-Ti and Al phases, and that the SPSed TiAl alloys contained the gamma TiAl and α2-Ti3Al phases. The TEM showed two different types of regions in the 16 h MAed Ti-46at.%Al powder. One type consisted of only Al with a grain size about 80 nm, and the other type a mixture of Al and Ti with a grain size of 30 nm. According to the optical micrographs of MA-SPSed samples, the alloys sintered at higher temperatures showed a coarser microstructure. In the case of the 1473 K sintering, typical duplex structures ((α2 + γ) lamella and γ phases) with interlamellar spacings of 50-400 nm and the grain size either less man 100 nm, or 1000 nm were observed.     

放电等离子烧结时间对高密度W-7Ni-3Fe合金组织性能的影响

利用放电等离子烧结技术制备高密度W-7Ni-3Fe合金,研究了烧结保温时间对合金致密度、物相、显微组织以及力学性能的影响。结果表明,在1200℃烧结5~14 min后,合金均能实现充分致密化,保温时间对相对密度影响较小。合金中的W晶粒随保温时间的延长开始尺寸变化不大,烧结11 min以上才明显长大,但大多数W晶粒尺寸仍小于5μm。烧结时间超过8min,合金中新出现一种灰色的富W组织。随保温时间延长,合金的洛氏硬度下降不大,然而抗弯强度却明显上升。合金弯曲断口形貌在较短保温时间以沿晶断裂为主,粘结相的延性撕裂和W晶粒的解理断裂随烧结时间延长逐渐增多。     

放电等离子烧结Ti-43Al-9V合金显微组织和力学性能(英文)

采用机械合金化和放电等离子烧结工艺制备细晶Ti-43Al-9V合金,研究不同烧结温度与显微组织和力学性能之间的关系。结果表明:机械球磨后粉末形状规则,尺寸在5～30μm之间,烧结所得块体材料主要由γ-TiAl、α2-Ti3Al和少量B2相组成。烧结温度为1150°C时,获得的等轴晶粒尺寸为300nm～1μm。烧结温度升高到1250°C时,等轴晶粒的尺寸明显增大,显微硬度从HV592降低到HV535,抗弯强度从605降低到219MPa,压缩断裂强度从2601降低到1905MPa,压缩率从28.95%降低到12.09%。     

钛锆钼合金与钨铼合金的SPS扩散焊接

采用放电等离子烧结(SPS)技术对TZM合金与WRe合金进行固相扩散焊接,研究了TZM/WRe接头的微观组织、力学性能和热疲劳性能. 结果表明,SPS扩散焊接技术在1 500 ℃保温30 min成功实现了TZM合金与WRe合金的高效连接,焊缝平整,无微裂纹、微孔洞和未焊合等焊接缺陷;TZM合金与WRe合金扩散焊接过程中均发生了再结晶,与W和Re相比,Mo具有较低的自扩散激活能,导致Mo的扩散深度大于W和Re在TZM合金中的扩散深度;TZM/WRe接头经历100次热震试验后,焊缝完好无裂纹,且部分再结晶Mo晶粒跨界生长;TZM/WRe接头的抗弯强度和抗剪强度分别为910 MPa±65 MPa,497 MPa±50 MPa,断裂失效发生在TZM合金一侧,断裂模式主要为穿晶解理断裂.     

SPS法制备p-型四元Al-Bi-Sb-Te合金的微结构与热电性能

采用SPS法制备了p-型四元Al-Bi-Sb-Te合金,研究其微结构和热电性能.结果表明:Al含量直接影响材料的电、热学输运性能.当材料中Al替代Sb元素后,四元合金AlxBi0.5Sb15-xTe3(x=0.05～0.2)的电导率明显增大;在室温附近,x=0.1的合金其电导率可达3.3×104Ω-1·m-1,大约是三元Bi0.5Sb1.5 Te3合金的2倍;四元合金系的最小Seebeck系数α为115μV/K,说明材料属p-型半导体;当温度为411 K时,合金AlxBi0.5-Sb1.5-xTe3(x=0.1)的ZT值出现最大值,其值为0.58,是同温度下典型三元Bi0.5Sb1.5Te3合金的1.6倍.     

生物医用多孔Ti-6Mo合金选择性激光烧结的结构特征和力学行为

采用选择性激光烧结金属元素Ti、Mo和粘结剂的混合粉末,制备了多孔Ti-6Mo合金,并研究了其结构特征和力学性能。结果表明,多孔Ti-6Mo合金的孔隙结构与烧结工艺有关,随着烧结温度从1000℃升高到1200℃,孔隙由三维连通孔变为相互孤立孔,孔隙率从58%下降到24%,孔径从112μm减小到43μm;多孔Ti-6Mo合金在室温为片层组织,均由大量α相和少数β相构成,并伴有微量α析出物;压缩应力-应变曲线表现为弹性变形、塑性屈服和断裂区三阶段,随着孔隙率降低,弹性模量和屈服强度分别在2.07~11.9 GPa和31.4~152.8 MPa增大,且相对弹性模量和相对屈服强度和相对密度之间遵循幂律关系。多孔Ti-6Mo合金的孔隙特征和力学性能均可满足自然骨要求,是一种可行的医用材料。     

Densification and properties of ODS-iron based alloy

Y₂O₃ dispersion strengthened iron-based powders and oxide dispersion strengthened（ODS） alloys were prepared by hydrothermal synthesis and spark plasma sintering（SPS）,respectively.The effects of Y₂O₃,vibratory milling treatment,and Ti element on the microstructure and mechanical properties of the materials were investigated by scanning electron microscope（SEM） and micro-electronic universal tester.The results show that the best mechanical properties are obtained with 1 wt.% Y₂O₃ addition.The size of agglomerated particles can be decreased to a certain degree by vibratory milling treatment.With the addition of Ti element,the tensile strength and hardness of the samples were improved.     

双步球磨与放电等离子烧结制备细晶TiAl合金

采用双步球磨法和放电等离子烧结(SPS)技术制备细晶Ti-47Al(at%)合金,利用扫描电子显微镜(SEM)、X射线衍射(XRD)仪以及透射电子显微镜(TEM)等分析测试手段对球磨后的粉末形貌结构、相组成以及烧结块体的显微组织结构进行观察和分析。结果表明:双步球磨粉末的颗粒形状较规则,其颗粒尺寸在20~40μm之间,内部结构均匀,主要由TiAl和Ti3Al相组成。放电等离子烧结后的块体主要由主相TiAl和少量的Ti3Al相及Ti2Al相组成,随着烧结温度的升高,Ti3Al相含量有所增加。当烧结温度为1000℃时,烧结块体获得的主要是等轴晶组织,等轴晶粒尺寸大多数在100~250nm之间。当烧结温度为1100℃时,烧结块体致密、无孔洞,等轴晶粒有明显长大的现象,显微组织主要由等轴状的TiAl相和片层状的Ti3Al相组成。