Phase Formation during Anneal of Supersaturated TiB2–CrB2–WB2Solid Solutions☆
Phase Formation during Anneal of Supersaturated TiB2–CrB2–WB2Solid Solutions☆
复制标题
过饱和 TiB2–CrB2–WB2 固溶体退火过程中相的形成☆
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
R. Telle
中科院分区：
文献类型：
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作者：
I. Mitra;R. Telle
Numerous transition metal diborides of AlB{sub 2} structure type reveal large mutual solid solubility. Temperature-depending homogeneity ranges bordering immiscibility gaps within the system TiB{sub 2}-CrB{sub 2}-WB{sub 2} provide the opportunity to tailor an in situ grown typical platelet-shaped phase emerging from a supersaturated host matrix. Results are presented where variations in composition, manufacturing parameters, and heat treatment lead to precipitates of a {open_quotes}W{sub 2}B{sub 5}{close_quotes} structure accompanied by the formation of another tungsten boride less rich in boron in a (Ti, W, Cr)B{sub 2} matrix. All phases are characterized by high melting points and hardness. The enhanced formation of the matrix as well as the precipitation mechanism were activated by the addition of 6 to 20 mule% CrB{sub 2} to the system TiB{sub 2}-WB{sub 2}. Within the ternary solid solution, a particular composition range exists exhibiting a thermal expansion behavior similar to boron carbide. Attempts are made to toughen boron and silicon carbide ceramics by processing this in situ growth of platelets out of dispersed transition metal diboride within a carbide matrix.
Numerous transition metal diborides of AlB{sub 2} structure type reveal large mutual solid solubility. Temperature-depending homogeneity ranges bordering immiscibility gaps within the system TiB{sub 2}-CrB{sub 2}-WB{sub 2} provide the opportunity to tailor an in situ grown typical platelet-shaped phase emerging from a supersaturated host matrix. Results are presented where variations in composition, manufacturing parameters, and heat treatment lead to precipitates of a {open_quotes}W{sub 2}B{sub 5}{close_quotes} structure accompanied by the formation of another tungsten boride less rich in boron in a (Ti, W, Cr)B{sub 2} matrix. All phases are characterized by high melting points and hardness. The enhanced formation of the matrix as well as the precipitation mechanism were activated by the addition of 6 to 20 mule% CrB{sub 2} to the system TiB{sub 2}-WB{sub 2}. Within the ternary solid solution, a particular composition range exists exhibiting a thermal expansion behavior similar to boron carbide. Attempts are made to toughen boron and silicon carbide ceramics by processing this in situ growth of platelets out of dispersed transition metal diboride within a carbide matrix.