Synthesis and mechanical properties of Ti3GeC2 and Ti3(SixGe1−x)C2 (x = 0.5, 0.75) solid solutions
Synthesis and mechanical properties of Ti3GeC2 and Ti3(SixGe1−x)C2 (x = 0.5, 0.75) solid solutions
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DOI：
10.1016/j.jallcom.2004.01.011
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发表时间：
2004-08
影响因子：
6.2
通讯作者：
A. Ganguly;T. Zhen;M. Barsoum
中科院分区：
文献类型：
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作者：
A. Ganguly;T. Zhen;M. Barsoum
In this paper we report on the synthesis and characterization of Ti3GeC2, Ti3Si0.5Ge0.5C2, and Ti3Si0.75Ge0.25C2solid solutions. Polycrystalline, fully dense, predominantly single phase samples of Ti3Si0.5Ge0.5C2, Ti3Si0.75Ge0.25C2, and Ti3GeC2of varying grain sizes were fabricated by reactive hot isostatic pressing (HIP) or hot pressing of Ti, C, SiC, and Ge powders. Based on the lattice parameter measurements we conclude that the extent of solid solubility in Ti3(SixGe1−x)C2ranges for x=0 to, at least, x=0.75. Since the hardness values of both solid solution compositions (2.5±0.2GPa) were in between those of Ti3SiC2(3.0±0.3GPa) and Ti3GeC2(2.2±0.5GPa) we conclude that no solid solution strengthening occurs in this system. All samples explored in this work were quite damage tolerant and thermal shock resistant. A 300N Vickers indentation in a 1.5mm thick, four-point bend bar decreases its strengths by anywhere from 25 to 35%. Quenching in water from 1000°C reduces the four-point flexural strength by 10 to 20%; i.e., it is not catastrophic. Notably, the post-quench flexural strength of the coarse-grained Ti3Si0.5Ge0.5C2samples was ≈25% higher than the as-received bars. Increasing the Ge content resulted in a decrease in the compressive strengths. The ultimate compressive strengths of fine-grained Ti3Si0.5Ge0.5C2samples, decreased monotonically from room temperature to ≈950°C. And while failure was brittle at room temperature, above 1000°C the loss in strength was more severe, but the deformation was more plastic.
