细晶粒TiCN-Co金属陶瓷的显微结构与力学性能

采用纳米TiN、亚微米TiC和Mo等原材料,以金属Co作为粘结剂,利用真空烧结技术制备了细晶粒Ti(C,N)基金属陶瓷材料,研究了所得金属陶瓷的显微结构和力学性能.结果显示:金属陶瓷的组织中有黑芯.灰壳结构和白芯.灰壳结构;Mo的加入使金属陶瓷的显微组织细化,当Mo的加入量为15%时,硬质相颗粒粒径小于lyre;15%的Mo加入量所得的细晶粒金属陶瓷与未加入Mo的金属陶瓷比较,其抗弯强度增加,硬度变化不明显,密度和断裂韧性降低.     

NiMo粘结的Ti(C,N)基金属陶瓷的组织与力学性能

本文通过粉末冶金法制备Ni Mo粘结的Ti(C,N)基金属陶瓷,研究Ni Mo粘结相含量和烧结温度对Ni Mo粘结的Ti(C,N)基金属陶瓷的组织和力学性能的影响。结果表明,随着Ni Mo粘结相含量的增加,硬质相颗粒弥散分布更加均匀,黑芯相得到细化,芯-环结构更加完整,环形相变厚,组织更加均匀。当Ni质量分数为30%时,在XRD图谱中出现明显的Ni4Mo类型的金属间化合物的衍射峰。粘结相含量越高,Ni Mo粘结的Ti(C,N)基金属陶瓷的抗弯强度越高,硬度越低。随着烧结温度升高,黑芯相尺寸变小,环形相变厚。抗弯强度随着温度先升高后降低,粘结相含量越高,抗弯强度峰值对应的烧结温度越低。1 430℃烧结的20Ni Mo金属陶瓷硬度HRA达到91,抗弯强度大于2 000 MPa。     

烧结温度和添加碳化物对NbC-Ni基金属陶瓷显微组织和力学性能的影响

本文报道了烧结温度和添加碳化物(VC、Mo_2C和TiC)以及Mo金属对一种新型NbC-Ni基金属陶瓷的致密化、NbC晶粒生长、显微组织演变以及维氏硬度(HV30)和断裂韧性的影响。所有的金属陶瓷均采用真空无压烧结制备,使用电子探针显微分析(EPMA)以及X射线衍射(XRD)来分析试样的微观组织、相组成及晶格常数的变化。结果表明,烧结温度,特别是添加碳化物的含量对NbC-Ni金属陶瓷的性能有显著的影响。当烧结温度低于1 340°C时,试样内存在Ni池和残余孔隙。温度高于1 380℃时,添加VC或Mo/Mo_2C的NbC-Ni基金属陶瓷达到完全致密,呈现出类似于WC-Co的两相组织结构。同时添加TiC+VC或TiC+Mo_2C的材料则形成一种含有芯环结构的NbC晶粒。相对于无添加的NbC-Ni金属陶瓷,添加体积分数5%~10%VC/Mo_2C和10%TiC能够明显提高材料的硬度和断裂韧性。     

烧结工艺和Y_2O_3添加量对Ti(C,N)基金属陶瓷显微组织和力学性能的影响

以TiC、TiN、Ni、Co等粉末为主要原料,以稀土Y2O3为添加剂,采用无压烧结技术制备Ti(C,N)基金属陶瓷,研究烧结工艺和稀土Y2O3添加量对Ti(C,N)基金属陶瓷显微组织和力学性能的影响。结果表明:随着温度的升高,TiC、TiN、WC、Cr3C2、Mo等相逐渐消失,向硬质芯相扩散发生固溶,经溶解-析出过程,最终形成新的Ti(C,N)硬质相和(Cr,W,Mo,Ti)(C,N)固溶体环形相,黏结金属Ni和Co主要以Ni相、TiCo和Co3W3C中间相的形式存在;稀土Y2O3的添加未改变Ti(C,N)基金属陶瓷烧结过程中的相结构演变过程,材料的显微硬度、抗弯强度和断裂韧性均随Y2O3添加量的增加呈先增加后降低的趋势,当Y2O3的加入量为0.8%(质量分数)时,Ti(C,N)基金属陶瓷的力学性能最佳,样品的显微硬度、抗弯强度和断裂韧性相比1450℃烧结50 min样品的分别提高了7.9%、45.8%和6.1%。     

压铸模具用复合金属陶瓷模具材料的研究

以微米TiC、TiN为主要原料,以纳米Y-ZrO2作为增强相,以微米Mo和Ni作为粘结相及微米C(石墨)和VC作为添加剂,采用热压烧成工艺来制备复合金属陶瓷模具材料。测试和分析了烧成样品的抗弯强度、硬度以及断裂韧性等性能,采用现代材料测试手段对烧成样品的显微结构进行了分析。结果表明,当TiC添加量(质量分数)为50.9%,TiN为22.5%、Y-ZrO2为5%时,所制备复合金属陶瓷模具材料性能最佳,相对密度值为97%,抗弯强度为1026 MPa,硬度为16.54 GPa,断裂韧性为9.86 MPa·m1/2。显微结构分析显示,样品微观晶粒形貌较致密,分布均匀。     

TiC粉末粒度对Ti（C,N）基金属陶瓷组织及性能的影响

通过采用真空烧结工艺的粉末冶金法制备了两组不同TiC粒度的Ti（C,N）基金属陶瓷材料。采用XRD、SEM、EDS研究了相结构和显微组织,测定了室温力学性能。结果表明,用纳米TiC粉末制备的金属陶瓷组织细小均匀,抗弯强度、硬度均较高,分别达1021.5 MPa和17.7 GPa（HV10）。     

一种纳米改性金属陶瓷材料的研究

研究了一种以TiC为基,纳米TiC和WC为改性剂,另加入Ni、Mo、Fe为粘结相的金属陶瓷耐磨材料,对该材料的强度、硬度和磁性进行了检测,并与相同成分的未加改性剂的TiC粒径≥2.4μm粗颗粒金属陶瓷进行了性能对比试验。结果表明:改性剂起到了明显的优化作用,经纳米改性后的金属陶瓷,既提高了强度、密度,也提高了硬度。     

铣削刀片用纳米改性金属陶瓷的显微组织和力学性能

研究了铣削刀片用纳米改性金属陶瓷的显微组织与力学性能。SEM观察结果表明,铣削刀片用纳米改性金属陶瓷组织仍由陶瓷相和金属相组成,其中粗大的陶瓷相颗粒为芯/壳结构;Mo元素添加能有效细化金属陶瓷陶瓷基体组织。抗弯测试表明,随金属相含量增加,金属陶瓷的抗弯强度和断裂韧性增加,而硬度则降低;断口分析可知,沿晶断裂为其主要的断裂方式。     

SHS-PHIP法制备TiC-Ni(Mo)金属陶瓷

采用Ti粉、碳黑、Ni粉和Mo粉的混合物，通过自蔓延高温合成(SHS)结合准等静压(PHIP)方法制备了TiC—Ni(Mo)金属陶瓷材料。X射线衍射结果表明，材料由TiC相和Ni合金粘结相组成。扫描电镜观察，球形的TiC颗粒较均匀地分布在Ni合金粘结相中,TiC颗粒尺寸约为2～4μm，在局部较大的TiC颗粒之间存在微孔缺陷。SHS—PHIP法制备的TiC—Ni(Mo)金属陶瓷材料具有良好的致密性和优良的力学性能。     

TiC基金属陶瓷配方的正交试验研究

通过正交试验法对TiC基金属陶瓷进行成分研究,选取抗弯强度为试验指标,进行极差分析,获得了最佳的TiC-WC-Cr3C2-Co-Ni-Mo金属陶瓷试验配方A2B3C1组合。试验表明Mo含量的增加使环形相增厚;Mo含量和Co/Ni含量比为抗弯强度的两个主要成分影响因素。     

Influence of Mo on the microstructure and mechanical properties of TiC-based cermets

The microstructures and mechanics properties of TiC-based cermets composed of TiC, WC, Ni, Co, Mo, and Cr₃C₂ were investigated. The results show that Mo has a great effect on the sintering densification, microstructures, and mechanical properties. The microstructures and distribution of Mo and Ti in the TiC-based cermets were analyzed. It was indicated that a new phase with Ti, Mo, W, and C was formed on the rim of (Ti,W)C grains by means of an addition of Mo into the TiC-based cermets. The new phase with a surrounding structure was of great aid to improve the wettability of the liquid phase on the solid phase surface of TiC, decrease the porosity and refine the grains of the hard phase, which gave rise to the increase in strength and hardness. The properties of the TiC-based cermets could be further improved to some extent by adding WC, Cr₂C₃, and Co.     

Effect of Mo addition on the microstructure and mechanical properties of ultra-fine grade TiC–TiN–WC–Mo2C–Co cermets

Effect of Mo addition on the microstructure and mechanical properties of ultra-fine grade TiC–TiN–WC–Mo₂C–Co cermets was studied in this work. Mechanical properties such as transverse rupture strength, fracture toughness and hardness were also measured. Results show that the microstructure exists in black core/grey rim structure and white core/grey rim structure, and the microstructure has an obvious trend to become finer with the increase of molybdenum content. When the added Mo exceeds 10%, ultra-fine TiC-based cermet with an average particle size of less than 0.5 μm is obtained, because of the formation of a Mo-rich rim and the improvement of the wettability between ceramic phase and metallic phase. The transverse rupture strength increases with the increase of Mo content, and the maximum values of the hardness and the fracture toughness were found with 10 wt% and 5 wt% Mo addition, respectively.     

Effect of Fe–Mo–Cr pre-alloyed powder on the microstructure and mechanical properties of TiC–high-Mn-steel cermet

In the study, a TiC–high-Mn-steel cermet is fabricated using FeMo and Fe–Mo–Cr pre-alloyed powders as metallic binders by powder metallurgy techniques. The effect of Cr on the microstructure and mechanical properties of the cermet is studied and the cermet preparation process is optimized. The microstructure and fracture morphology of the cermets are observed with scanning electron microscopy, while phase identification and analysis are performed by X-ray diffractometry. The results show that the particles of Cr-free cermet are angular and polygonal, while those of cermet with added Cr are rounded and ellipsoidal. The grains of Cr-free cermet are larger than those of the Cr-added cermet, which is unlike similar conventional cermets. The grain size of the Cr-added cermet increases slightly with increased Cr content. In addition, the relative density of the cermet decreases slightly with increased Cr content. The hardness of cermet is maximized at HRC 64.8 with the Cr content of 1.0 wt%; with further increases in Cr, the hardness decreases gradually. The transverse rupture strength and impact toughness first increase and then decrease with increasing Cr content, reaching the maxima of 2355 MPa and 13.42 J/cm², respectively, at the Cr content of 1.5 wt%. The strength and toughness of the cermet are improved greatly compared to those of conventional similar TiC–high-Mn-steel cermets.     

Ni_3Al粘结相对Ti(C,N)基金属陶瓷组织性能的影响

采用粉末冶金法制备了Ni3Al做粘结相的Ti(C,N)基金属陶瓷,研究了添加不同含量Ni3Al粘结相的金属陶瓷的力学性能和显微组织并与Ni做粘结相的金属陶瓷进行了对比。结果表明,Ni3Al作粘结相的金属陶瓷综合力学性能总体上不如Ni做粘结相的金属陶瓷,随着金属陶瓷中Ni3Al含量的增加,其洛氏硬度值不断下降,而抗弯强度和断裂韧性却不断增加;显微组织分析表明,Ni3Al做粘结相的金属陶瓷同样具有芯环结构,Ni3Al可以控制环形相的厚度,抑制晶粒异常长大,使硬质相芯相棱角圆润。Ni3Al含量为30wt%左右的金属陶瓷能够兼顾硬度和抗弯强度等力学性能,此时的主要力学性能指标为:抗弯强度1 045±80 MPa,洛氏硬度HRA89.7±0.25,断裂韧性KIC为14.26 MPa·m1/2。     

原始粉末粒度组合对Ti(C,N)基金属陶瓷组织和性能的影响

采用粉末冶金方法制备了Ti(C,N)基金属陶瓷,研究了TiC和TiN在不同粒度组合下,Ti(C,N)基金属陶瓷的组织和性能。利用SEM、XRD等分析手段对所制备的金属陶瓷进行分析。结果表明,采用微米级TiC和纳米级TiN粒度组合得到的Ti(C,N)基金属陶瓷综合力学性能最好。其抗弯强度达到了1 052.8 MPa,断裂韧性达到了9.3 MPa·m1/2。     

EFFECT OF Mo AND Mo2C ON THE MICROSTRUCTURE AND PROPERTIES OF THE CERMETS BASED ON Ti（C,N）

Effect of Mo and Mo2 C on the microstructure and properties of Ti（C,N）-based cermets was investigated in this article. The results have indicated that the weight percentage of Mo from 5 to 10 can reduce Ti（C,N） grain diameter and thickness of the rim, and Ti（C,N） grain can be wetted by Ni-Cu-Mo liquid so as to get small contiguity of Ti（C,N） grain. In that way, the transverse rupture strength of Ti（C,N）-based cermets has reached 1800-1900 MPa; the fracture toughness has been due to 16-18 MPa.m1/2. But 15 wt pct Mo was not more effective on Ti（C,N）-based cermets, because the thickness of the rim becomes larger. In the circumstance of Mo2 C, 5 wt pct Mo2 C was good for microstructure and properties of Ti（C,N）-based cermets, but 11 wt pct Mo2C has resulted in larger contiguity of Ti（C,N） grain and big Ti（C,N） grain diameter so as to reduce transverse rupture strength and fracture toughness. So that, the effect of Mo on Ti（C,N）-based cermets is better than Mo2C.     

Ti(C,N)基金属陶瓷的芯-壳显微结构与性能研究

以TiC、TiN为原料,Ni、Co为粘结剂,WC、Mo2C、TaC、C、Cr3C2为添加剂,采用真空热压烧结工艺制备Ti(C,N)基金属陶瓷材料。借助于SEM、EDS和XRD分别分析其显微结构、组成和物相,并测试其性能。结果表明:按配方(质量分数,%):TiC:41.2,TiN:10,Ni:7,Co:7,Mo2C:12,WC:15,TaC:6,Cr2C3:0.8,C:1配料,在1450℃,30MPa热压制得的试样晶粒细小,具有完整的芯-壳显微结构。其主要性能为:相对密度99.12%,维氏硬度22.74GPa,断裂韧性10.1MPa·m1/2,抗弯强度1192.83MPa。     

Effect of hard phase content on the mechanical properties of TiC-316 L stainless steel cermets

The dense TiC-316 L stainless steel cermets with different TiC content were fabricated via conventional powder metallurgy (PM) process. The effects of TiC content on the microstructure and mechanical properties of TiC-316 L stainless steel cermets are studied. Scanning electron microscopy (SEM) is employed to observe the microstructure, fracture morphology, and crack propagation of cermets. The binder mean free path (MFP) and hard phase contiguity are analyzed based on the stereological principles. The relative density, hardness and transverse rupture strength (TRS) of the cermets are measured by the Archimedes' principle, Rockwell scale hardness tester and three-point flexural test, respectively. The average TiC grain size decreases first and then increases with the increase of hard phase content. At a content of 80 wt%, the maximum relative density (99.1%), hardness (88.9 HRA) and TRS (1373 MPa) are obtained. During crack propagation, both intergranular and transgranular fractures exist, of which the intergranular fracture prevail and coarse grains are more prone to transgranular fracture.     

ZrC含量对TiC基金属陶瓷组织和性能的影响

真空烧结制备了TiC-ZrC-Co-Ni系金属陶瓷,研究了ZrC对TiC基金属陶瓷显微组织和室温力学性能的影响。结果表明:未加ZrC的TiC基金属陶瓷的显微组织表现为经典的黑芯-灰壳组织,硬质相形状多为球形;而加入ZrC后的金属陶瓷随着ZrC加入量的增多,组织逐渐细化,硬质相形状大多数为方形,硬质相与粘结相界面呈现直线,在黑芯周围出现白色球状(Ti,Zr)C固溶体。由于Co、Ni对ZrC的润湿性不理想,金属陶瓷的致密度随着ZrC含量的增加而下降,室温力学性能(抗弯强度、硬度、断裂韧性)也随之降低。