The dependences of the microstructure and hardness of the binary Cr Ta alloys [Cr 9.0, 9.2, 9.4, 9.6, 9.8, and 13.0 Ta] (mole fraction, %) were investigated. When Ta content of the alloy is less than 9.4%, there are p...The dependences of the microstructure and hardness of the binary Cr Ta alloys [Cr 9.0, 9.2, 9.4, 9.6, 9.8, and 13.0 Ta] (mole fraction, %) were investigated. When Ta content of the alloy is less than 9.4%, there are primary dendrite grains of a Cr solid solution phase existing in the matrix of Cr Cr 2Ta eutectic colonies in the alloy. Moreover, the regular polygon grains of the primary Cr 2Ta Laves phase are surrounded by the Cr Cr 2Ta eutectic colony in the hyper eutectic Cr 9.4% Ta alloys. The scanning electron microphotograph shows that one of the Cr 2Ta phase plates of an eutectic colony always connects with the primary Cr 2Ta Laves phase grain in a hyper eutectic alloy. The eutectic colony size of Cr Ta alloys decreases with increasing Ta. In addition, the macrohardness of Cr Ta alloys is influenced by the chemical composition at room temperature. The binary eutectic Cr Ta alloy presents the lowest hardness on a macrohardness scale.展开更多
文摘The dependences of the microstructure and hardness of the binary Cr Ta alloys [Cr 9.0, 9.2, 9.4, 9.6, 9.8, and 13.0 Ta] (mole fraction, %) were investigated. When Ta content of the alloy is less than 9.4%, there are primary dendrite grains of a Cr solid solution phase existing in the matrix of Cr Cr 2Ta eutectic colonies in the alloy. Moreover, the regular polygon grains of the primary Cr 2Ta Laves phase are surrounded by the Cr Cr 2Ta eutectic colony in the hyper eutectic Cr 9.4% Ta alloys. The scanning electron microphotograph shows that one of the Cr 2Ta phase plates of an eutectic colony always connects with the primary Cr 2Ta Laves phase grain in a hyper eutectic alloy. The eutectic colony size of Cr Ta alloys decreases with increasing Ta. In addition, the macrohardness of Cr Ta alloys is influenced by the chemical composition at room temperature. The binary eutectic Cr Ta alloy presents the lowest hardness on a macrohardness scale.