混合稀土和Ce对Ni_3Al合金氧化行为和力学性能的影响

EFFECT OF RE AND Ce ON OXIDATION BEHAVIOR AND MECHANICAL PROPERTIES OF Ni_3Al ALLOY

本文研究了不同含量混合 RE 和 Ce 对 Ni_3Al-B 和 Ni_3Al-B-Cr-Zr 合金在1050℃,0.1MPa 下氧化行为的影响,以及混合 RE 对 Ni_3Al-B-Cr-Zr 合金不同温度下瞬时拉伸性能的影响。结果表明,合金中加入少量的稀土元素,促进 Al_2O_3形核,加速致密氧化膜形成,提高合金的抗氧化性。混合 RE 以固溶方式进入氧化膜,细化 NiO 和 Al_2O_3晶粒,增加塑性,不易剥落。少量 Ce 加入 Ni_3Al-B-Cr-Zr 合金,有利于形成细小密集“树根状”氧化物,使氧化膜紧密粘附在基体金属表面。加入0.1%RE 使Ni_3Al-B-Cr-Zr 合金低温抗张强度升高,对塑性影响不大,但对高温强度和塑性有害。

This paper studied the effect of various content of RE and Ce on the oxidationbehavior of Ni_3Al-B and Ni_3Al-B-Cr-Zr alloys at 1050℃ and 0.1MPa,respectively.The resultsshow that adding small amount of rear earth element can promote the nucleation of Al_2O_3,ac-celerate the formation of density oxidation layer,increase oxidation resistance of the alloy.RE_soluted in the oxidation layer fines the grains of NiO and Al_2O_3,increases the ductility of oxidefilm,so that makes it cohensive.Small amount of Ce added in NI_3AI-B-Cr-Zr alloy is benefi-cial to formation of fine,density“tree roots”oxides,which improves scale adherence tosubstrate.Adding RE to Ni_3Al-B-Cr-Zr alloy increases the ultimated strength below 400℃.But it is harmful to its strength and ductility at high-temperature.