Synthesis and high-temperature stability of titanium aluminide matrixin situ composites
Synthesis and high-temperature stability of titanium aluminide matrixin situ composites
复制标题
铝化钛基原位复合材料的合成及高温稳定性
DOI：
10.1007/bf02646777
复制
发表时间：
1992
影响因子：
3.1
通讯作者：
N. Mohri
中科院分区：
文献类型：
--
作者：
Y. Tsunekawa;K. Gotoh;M. Okumiya;N. Mohri
采用氮、氢混合等离子体气体反应低压等离子喷涂的方法，将钛、铝元素粉末的预混料作为喷涂材料直接制备钛铝基复合材料。预混料中的铝含量从10%到63%不等。喷涂层基体由ti3a1、TiAl和tial3三种钛铝化物组成，沉积后立即在低碳钢基体上形成。作为强化物的氮化物的形成既发生在液滴的飞行过程中，也发生在基体上。在喷射的金属间基复合材料中，无论预混料的铝含量如何，氮含量约为4%至5%。预混料中铝的含量决定了钛铝化物的种类。采用真空退火的方法改善了喷涂金属间基复合材料中铝和钛的均匀性。经退火处理后，ti - 36wt .% AI预混料喷涂的金属间基复合材料中形成的主要TiAl相数量增加。在退火过程中，少量氮化物消失，而主要的强化物Ti2AlN不但没有分解，反而增加了。喷镀金属间基复合材料的硬度随预混料中铝含量的变化而变化，但总大于不含氮化物的喷镀钛铝化物的硬度。退火不降低喷涂金属间基复合材料的硬度。ti - 36wt .% Al预混料的喷涂和退火金属间基复合材料在800k时硬度保持在500 HV左右。因此，反应性低压等离子喷涂为钛铝基复合材料提供了一种很有前途的制造方法，有望在高温下具有优异的耐磨性应用。
A premixture of elemental powders of titanium and aluminum was supplied as a spray material for the direct fabrication of titanium aluminide matrixin situcomposites by means of reactive low-pressure plasma spraying with a nitrogen and hydrogen mixed plasma gas. The aluminum content varied from 10 to 63 wt.% in the premixtures. The matrix of sprayed layers consisted of three kinds of titanium aluminides—Ti3A1, TiAl, and TiAl3—which begin to form on a low-carbon steel substrate immediately after deposition. The formation of nitrides, which act as a reinforcement, occurs both during the flight of liquid droplets and on the substrate. The nitrogen content is approximately 4 to 5 wt.% in the sprayed intermetallic matrix composites, regardless of the aluminum content of the premixtures. The kinds of titanium aluminides andin situnitrides developed depend on the aluminum content of the premixtures. The homogeneity of the distribution of aluminum and titanium in sprayed intermetallic matrix composites has been improved by vacuum annealing. The predominant TiAl phase that formed in the sprayed intermetallic matrix composites with a Ti-36 wt.% AI premixture increases in quantity through annealing. Although some minor nitrides disappear through annealing, the principal reinforcement, Ti2AlN, does not decompose, but increases in quantity. The hardness of sprayed intermetallic matrix composites varies with aluminum content of the premixtures, but is always greater than that of sprayed titanium aluminides containing no nitrides. Annealing does not reduce the hardness of sprayed intermetallic matrix composites. Sprayed and annealed intermetallic matrix composites with a Ti-36 wt.% Al premixture maintain their hardness of approximately 500 HV up to 800 K. Hence, reactive low-pressure plasma spraying offers a promising fabrication method for titanium aluminide matrixin situcomposites, which are expected to excel in wear resistance applications at elevated temperatures.