对上述试样进行EDS成分分析,结 果如图5所示.观察图 5(a)中 Spectrum1 处的基体可见灰色基体中有黑色相.结合 XRD 分析、显微硬度测试、EDS 分析结果,可以判断：图5(a)和(b)中所示灰色基体由NiAl金

对上述试样进行EDS成分分析,结 果如图5所示.观察图 5(a)中 Spectrum1 处的基体可见灰色基体中有黑色相.结合 XRD 分析、显微硬度测试、EDS 分析结果,可以判断：图5(a)和(b)中所示灰色基体由NiAl金
对上述试样进行EDS成分分析,结 果如图5所示.观察图 5(a)中 Spectrum1 处的基体可见灰色基体中有黑色相.结合 XRD 分析、显微硬度测试、EDS 分析结果,可以判断：图5(a)和(b)中所示灰色基体由NiAl金属间化合物和 Al2O3 陶瓷两相组成,深灰色相为NiAl 金属间化合物,无晶界显示,而黑色相为Al2O3,呈无规则形状；图 5(c)中白色规则颗粒皆为TiB2.T iB2的形态种类较多,有类正六方体、类六棱柱体和棒条状,最小的比较完整的颗粒尺寸为2~5 μm,主要镶嵌在无规则的 Al2O3 相中,还有一些 TiB2 颗粒分布在NiAl 基体上,尺寸为5~10 μm.
在反应混合物中Al 的颗粒较大,为70~230 mm,但生成的 TiB2 颗粒却很小,大部分尺寸小于 5 μm,主要呈簇状镶嵌在 Al2O3 基体上,由此推断 Al2O3 和TiB2 是相伴生长的.TiB2 团簇的尺寸为10~20 mm,远远小于Al 颗粒的尺寸.对于 NiAl摩尔比为 1:1 的体系,室温下引发反应,体系的绝热温度 Tad=Tm,NiAl=1 911 K [19] ；而对于AlTiO2B2O3
摩尔比为 10:3:3 的体系,室温下引发反应,反应的绝热温度Tad=2 448 K [20] .对试样300 ℃预热,根据文献[21]热力学数据计算混合体系 NiAl+AlTiO2B2O3的绝热温度,随着 AlTiO2B2O3含量的增加,体系绝热温度升高,当 AlTiO2B2O3的质量分数由10%增加至30%时,其 Tad 由2 684 K升高至2 723K,介于Al2O3 和TiB2 的熔点之间.

对上述试样进行EDS成分分析,结 果如图5所示.观察图 5(a)中 Spectrum1 处的基体可见灰色基体中有黑色相.结合 XRD 分析、显微硬度测试、EDS 分析结果,可以判断：图5(a)和(b)中所示灰色基体由NiAl金
analyzing the EDS composition of above samples,the result as shown in Figure 5.Observe the basical body at Spectrum 1 in Figure 5(a),black phases can be seen in the gray basical body.Combining the result of XRD analysis,hardness test and EDS composition anlysis,we can judge that :the gray basical body shown in Fig.5 (a)and (b) is composed of NiAl intermetallic compounds and Al2O3 ceramic phases,in which the dark gray phases are NiAl intermetallic compounds with no display of grainboundary,while the black phases are Al2O3 in irregular shape; the white particles in regular shape shown in Fig.5(C)are all TiB2.TiB2 is of great morphological diversity,including cube hexahedron,six - sided prism,or bar shape.the minimum size of a comprehensive particle is 5 μm,mainly inserted in the irregular AI203 phases,while some were distributed onto the basical body sized 10 μm.
The AI particles are with comparetively bigger size of 70~230 mm among the reaction mixture,however,the TiB2 particles generated by reaction were very small,mostly are smaller than 5 μm and clustered on the basical body of Al2O3.Thus,we deducted that Al2O3 and TiB2 have grown together.The size of the clustered TiB2 is 10~20 mm,which is far less smaller than the size of AI particles.For the molar ratio of 1:1 NiAl system to initiate reaction under room temperature,the adiabatic temperature is Tad=Tm,NiAl=1 911 K [19]; while the molar ratio of 10:3:3 AlTiO2B2O3 system to initiate reaction under room temperature,the adiabatic temperature is Tad=2 448 K [20].Preheating the samples under 300 ℃,and calculate the adiabatic temperature of hybrid system NiAl+AlTiO2B2O3 according to the thermodynamic data provided in Ref.[21],with the amount content of AlTiO2B2O3 increasing,the adiabatic temperature rises.When the mass fraction of AlTiO2B2O3 increases from 10% to 30%,the Tad rises from 2648K to 2723K,which is between the Melting point of Al2O3 and TiB2.