铸态和快淬Ti基贮氢合金的放电容量与显微结构

Discharge capacity and microstructure of cast and quenching Ti-based hydrogen-storage alloy

快淬工艺能明显地提高Ti0 .8Zr0 .2 Mn0 .5V0 .5Ni1.0 贮氢合金的放电容量 ,而且淬速与放电容量之间在一定情况下出现峰值。XRD、SEM、TEM分析结果表明 :快淬合金由细小的枝晶组成 ,随着淬速增加 ,晶粒更加细小 ;快淬合金很难形成非晶 ,当淬速达到 32m/s时仅有少量非晶出现 ,主体仍是微晶和纳米晶 ;Ti0 .8Zr0 .2 Mn0 .5V0 .5Ni1.0 合金是多相结构 ,低淬速快淬态合金和铸态合金由大量的六方C14Laves相和少量的TiNi非Laves相组成 ,当淬速达到 8m/s时 ,合金中开始出现立方C15Laves相。快淬合金中能大量吸氢的C14、C15相的总含量更多 ,从而使快淬钛基合金的放电容量有较大的提高。合金中各个相的相对含量随着淬速的改变而改变 ,使C14。

The discharge capacity of Ti 0.8Zr 0.2Mn 0.5V 0.5Ni 1.0 alloy was greatly improved by rapid-quenching, and its peak value can be achieved at certain rapid rate. The microstructure of as-quenching alloy was observed by XRD, SEM and TEM. The results show that: 1) the dendritic crystal will be finer with increasing rapid rate; 2) small quantity of amorphous appears only at the quench rate of 32 m/s, the main of alloy still consists of microcrystallite and nanocrystal; 3) both of as-cast alloy and low rate as-quenching alloy are polyphase structure(larger quantity of C14, a little of TiNi), and C15 phase appears under the rate above 8 m/s, and more content of C14+C15 phases greatly improves the discharge capacity. With the quenching rate changing, the relative content of each phase is changed, so the relationship between the content of C14+C15 and the rapid quenching rate is not simply lineal.