摘要
利用X射线衍射仪(XRD)、金相显微镜(OM)、维氏硬度计和万能电子拉伸试验机,研究了N i47Ti44Nb9形状记忆合金冷轧板材中的B2相沿轧向(RD)和横向(TD)的织构,以及热处理对冷轧板材硬度、显微组织、拉伸性能和恢复应变的影响。结果表明:冷轧板材的织构主要由较强的{111}<uvw>丝(即γ-丝)和较弱的{332}<uvw>丝组成。沿轧向,强组分向γ-丝中的{111}<110>靠近,而沿横向,强组分靠近γ-丝中的{111}<112>;随淬火温度提高,冷轧板材的硬度缓慢下降,超过500℃后,硬度急剧下降,到700℃以后硬度基本不变;冷轧板材在550℃发生明显再结晶,700℃处理后再结晶晶粒发生长大;随淬火温度提高,沿轧向(RD)和横向(TD)的应力诱发马氏体相变临界应力(σM)和可恢复应变(εr)降低。低于550℃淬火板材,沿轧向的临界应力σM高于沿横向方向的,而沿横向的可恢复应变εr较高,高于550℃淬火,沿横向的临界应力σM提高,可恢复应变εr沿轧向和横向的数值接近。
Textures of cold-rolled Ni47Ti44Nb9 shape memory alloy sheet along rolled（RD） and transverse（TD） directions and influence of heat treatment on hardness,microstructure,tensile properties and recovery strain were studied by X-ray diffraction（XRD）,optical microscopy（OM）,HV hardness tester and electronic universal tensile testing machine.The results showed that textures of cold-rolled sheet mainly consisted of stronger {111} uvw（or γ-fibre） and weaker {332} uvw fibers.Strong components approached to {111} 110 along RD and {111} 112 in γ-fibre along TD.With increasing quenching temperature,hardness first slowly decreased,then rapidly reduced at temperature more than 500 ℃,at last,kept fundamentally constant at temperature more than 700 ℃.The cold-rolled sheet occurred obvious recrystallization at 550 ℃ and recrystallized grains grew at 700 ℃.With the increase of quenching temperature,the critical stress of stress-induced martensite transformation（σM） and recovery strain（εr） decreased along RD and TD.The critical stress σM along RD was higher than that along TD and recovery strain εr was greater along TD for sheets quenched at temperature less than 550 ℃.And when quenching temperature was more than 550 ℃,σM enhanced along TD and εr along RD and TD were near.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2011年第3期368-372,共5页
Chinese Journal of Rare Metals
基金
核燃料及材料国防科技重点实验室基金资助项目(51481130101ZK0601)
