La-TZM合金板材制备及其氧化行为

采用粉末冶金法,在TZM合金的基础上,固-液掺杂稀土元素La,且以有机碳源硬脂酸替代传统的石墨粉引入C元素,经混料、压制成形、高温烧结、热轧、温轧、冷轧等工艺制备La-TZM合金板材。将La-TZM合金板材分别在300、450、600、800、1000℃进行高温氧化实验,通过质量损失率、差热分析等实验方法研究其氧化行为。研究表明:La-TZM合金板材的抗拉强度为1361.74 MPa,伸长率为8.81%,较传统的TZM合金均有显著提高。La-TZM合金板材纤维组织细长,组织致密;第二相细小且分布均匀。其细小的氧化镧及第二相颗粒钉扎在晶界,生成的氧化物会在基体表面形成致密氧化物覆盖层,可以有效地阻碍氧向基体的侵入,表面不易氧化,从而使TZM合金的抗氧化性能提高,扩展了TZM合金的使用温度范围。

Preparation and Oxidation Behavior of La-TZM Alloy Plates

Based on TZM molybdenum alloy, powder metallurgy methods were using to prepare La-TZM alloy plates with solid-liquid doped rare earth lanthanum and substitution of organic carbon stearic for traditional graphite by mixing, pressing and sintering, hot-rolling, warm-rolling, and cold rolling. La-TZM alloy plates were heated at 300, 450, 600, 800 and 1000 oC in the furnace to calculate the mass loss of the samples. The oxidation behavior was analyzed by the differential thermal analysis. The results show that the tensile strength and elongation of La-TZM plate are 1361.74 MPa and 8.81%, respectively, higher than those of traditional TZM plate. The fiber of La-TZM alloy plate is slim and homogeneous. The second phase of La-TZM alloy plate is smaller and disperses homogeneously. The La-TZM alloy has a more compact structure due to the lanthanum doping. The minute lanthanum oxide particles are pinned at the grain boundaries and refine the grains. Oxide layer generated on the matrix surface can form a compact coating, which effectively blocks the surface from being corroded by oxidation. The oxidation resistance of La-TZM alloys is enhanced, expanding its application range