铸态和快淬Ti基贮氢合金的放电容量与显微结构

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、C15相的总含量与淬速之间并不是简单的线性关系

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

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.