Al_(2)O_(3)掺杂钼丝的制备与性能研究

Research on Preparation and Properties of Al_(2)O_(3)-doped Molybdenum Wire

为了提高钼丝的性能,以四钼酸铵、硝酸、硝酸铝、尿素为原料,采用水热法制备MoO_(3)-Al_(2)O_(3)前驱体,再经低温煅烧、两段氢气还原获得Mo-Al_(2)O_(3)复合粉体,随后采用压制和高温烧结获得约φ20mm的Mo-Al_(2)O_(3)钼棒,最后经开坯、旋锻、拉拔、退火、冷拉制得φ0.18mm的Mo-Al_(2)O_(3)钼丝。研究了不同Al_(2)O_(3)掺杂量对钼粉及钼丝组织和性能的影响,分析了钼丝的强化机理。结果表明,添加Al_(2)O_(3)颗粒可以细化Mo晶粒和提高钼丝性能,且Al_(2)O_(3)颗粒添加量越大,Mo-Al_(2)O_(3)晶粒细化程度越大,钼丝力学性能越优异。Al_(2)O_(3)掺杂钼丝的强化机理为弥散强化、细晶强化、加工硬化和织构强化,它们共同赋予了Al_(2)O_(3)颗粒增强钼丝超高的强度。实验范围内,Mo-0.25%Al_(2)O_(3)的抗拉强度和延伸率最高,分别达到2243MPa和3.9%。

In order to improve the properties of molybdenum wire,using ammonium tetramolybdate,nitric acid,aluminum nitrate and urea as raw materials,MoO_(3)-Al_(2)O_(3) precursor was prepared by hydrothermal method,and then Mo-Al_(2)O_(3) composite powder was obtained by low temperature calcination and two-stage hydrogen reduction.Then,the Mo-Al_(2)O_(3) molybdenum rod with a diameter of about 20mm was obtained by pressing and high temperature sintering,and finally the Mo-Al_(2)O_(3) molybdenum wire with a diameter of 0.18mm was obtained by blanking,rotary forging,drawing,annealing and cold drawing.The effects of different Al_(2)O_(3) doping contents on the microstructure and properties of molybdenum powder and molybde-num wire were studied,and the strengthening mechanism of molybdenum wire was analyzed.The results show that the addition of Al_(2)O_(3) particles can refine Mo grains and improve the properties of molybdenum wire.The more the addition amount of Al_(2)O_(3) particles,the greater the grain refinement degree of Mo-Al_(2)O_(3),and the better the mechanical properties of molybdenum wire.The strengthening mechanism of Al_(2)O_(3)-doped molybdenum wire is dispersion strengthening,grain refinement strengthening,work harden-ing and texture strengthening,which together endow the Al_(2)O_(3)-doped molybdenum wire with ultra-high strength.Within the experimental range,the tensile strength and elongation of Mo-0.25%Al_(2)O_(3)are the highest,reaching 2243MPa and 3.9%,respectively.