Abstract

The structure and phase composition of a material obtained via SHS in the combustion of a 87% Ti + 13% B powder mixture with the addition of Si₃N₄ is under study. The phase formation mechanism in this system is discussed. It is established that the material contains 64% of the TiB phase with an orthorhombic structure and 36% of the solid boron solution in titanium (\(\alpha\)-Ti[B]). The boron content in \(\alpha\)-Ti significantly exceeds its equilibrium content according to a state diagram. In the case of combustion of an 87% Ti + 13% B mixture with the addition of 5% Si₃N₄, the finite product contains TiB, \(\alpha\)-Ti[B], TiB₂, and Ti₅Si₃ phase. The TiB phase is present in the form of two modifications: orthorhombic and cubic. The completeness of a structural transition of the cubic modification of TiB into an orthorhombic one is determined by the cooling rate of a sample. It is assumed that the combustion of the mixture with the addition of Si₃N₄ forms the dispersed discharges of TiN, which are the crystallization centers of cubic TiB.

中文翻译：

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含Si 3 N 4的Ti-B混合物在SHS中的相形成

摘要

通过SHS在87％Ti + 13％B粉末混合物中添加Si ₃ N ₄的燃烧中获得的材料的结构和相组成正在研究中。讨论了该系统中的相形成机理。已经确定该材料包含具有正交晶结构的TiB相的64％和钛中固态硼溶液（\（\ alpha \）- Ti [B]）的36％。根据状态图，\（\ alpha \）- Ti中的硼含量大大超过其平衡含量。在燃烧87％Ti + 13％B混合物并添加5％Si ₃ N _{4的情况下}，有限产物包含TiB，\（\ alpha \）- Ti [B]，TiB ₂和Ti ₅ Si ₃相。TiB相以两种变体形式存在：正交晶和立方晶。TiB的立方变体转变为正交晶体的结构转变的完整性取决于样品的冷却速率。假定混合物中加入Si ₃ N ₄的燃烧形成了TiN的分散排放物，它们是立方TiB的结晶中心。