中国有色金属学报(英文版)
中國有色金屬學報(英文版)
중국유색금속학보(영문판)
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
2015年
6期
1831-1839
,共9页
吴懿萍%张新明%邓运来%唐昌平%杨柳%仲莹莹
吳懿萍%張新明%鄧運來%唐昌平%楊柳%仲瑩瑩
오의평%장신명%산운래%당창평%양류%중형형
Mg-RE合金%热压缩%孪晶%动态再结晶机制
Mg-RE閤金%熱壓縮%孿晶%動態再結晶機製
Mg-RE합금%열압축%련정%동태재결정궤제
Mg-RE alloy%hot compression%twin%dynamic recrystallization mechanism
在变形温度为450°C和应变速率为2 s?1的条件下对均匀化退火后的Mg?7Gd?4Y?1Nd?0.5Zr合金进行热压缩试验。采用金相显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)综合分析合金变形过程中的动态再结晶机制。采用电子背散射衍射(EBSD)获得晶体微取向信息。结果表明:随应变逐渐增加到?1.88,合金流变应力先快速升高到某个峰值,随后下降到最低值,最后又开始逐渐上升。在低应变下,大量{1012}拉伸孪晶诱发形核形成动态再结晶晶粒,导致晶粒明显细化。动态再结晶晶粒首先在孪晶边界进行形核,且与孪晶母体存在30°?0001?的取向差。在大应变下,合金组织中在原始大晶粒附近形成细小动态再结晶晶粒,且从原始大晶粒内部到其晶界处的累积微取向连续增加,从而确定合金发生了连续动态再结晶。合金中也发现了粒子激发形核的动态再结晶机制。
在變形溫度為450°C和應變速率為2 s?1的條件下對均勻化退火後的Mg?7Gd?4Y?1Nd?0.5Zr閤金進行熱壓縮試驗。採用金相顯微鏡(OM)、掃描電鏡(SEM)和透射電鏡(TEM)綜閤分析閤金變形過程中的動態再結晶機製。採用電子揹散射衍射(EBSD)穫得晶體微取嚮信息。結果錶明:隨應變逐漸增加到?1.88,閤金流變應力先快速升高到某箇峰值,隨後下降到最低值,最後又開始逐漸上升。在低應變下,大量{1012}拉伸孿晶誘髮形覈形成動態再結晶晶粒,導緻晶粒明顯細化。動態再結晶晶粒首先在孿晶邊界進行形覈,且與孿晶母體存在30°?0001?的取嚮差。在大應變下,閤金組織中在原始大晶粒附近形成細小動態再結晶晶粒,且從原始大晶粒內部到其晶界處的纍積微取嚮連續增加,從而確定閤金髮生瞭連續動態再結晶。閤金中也髮現瞭粒子激髮形覈的動態再結晶機製。
재변형온도위450°C화응변속솔위2 s?1적조건하대균균화퇴화후적Mg?7Gd?4Y?1Nd?0.5Zr합금진행열압축시험。채용금상현미경(OM)、소묘전경(SEM)화투사전경(TEM)종합분석합금변형과정중적동태재결정궤제。채용전자배산사연사(EBSD)획득정체미취향신식。결과표명:수응변축점증가도?1.88,합금류변응력선쾌속승고도모개봉치,수후하강도최저치,최후우개시축점상승。재저응변하,대량{1012}랍신련정유발형핵형성동태재결정정립,도치정립명현세화。동태재결정정립수선재련정변계진행형핵,차여련정모체존재30°?0001?적취향차。재대응변하,합금조직중재원시대정립부근형성세소동태재결정정립,차종원시대정립내부도기정계처적루적미취향련속증가,종이학정합금발생료련속동태재결정。합금중야발현료입자격발형핵적동태재결정궤제。
Hot compression tests were conducted on a homogenized Mg?7Gd?4Y?1Nd?0.5Zr alloy at 450 °C and a strain rate of 2 s?1. Dynamic recrystallization (DRX) mechanisms were investigated by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM) systematically. The crystallographic orientation information is obtained through electron back-scattering diffraction (EBSD). The result shows that the flow stress firstly reaches a peak rapidly followed by declining to a valley, and then increases gradually again when the alloy is compressed to a strain of?1.88. DRX related to{1012} tensile twins is extensively observed at small strains, resulting in an evident grain refinement. DRX grains first nucleate along the edges of twin boundaries with about 30°?0001? off the twin parents. While at large strains, conventional continuous DRX (CDRX) is frequently identified by the formation of small DRX grains along the original grain boundaries and the continuously increasing misorientation from the centre of large original grains to the grain boundaries. Evidence of particle-stimulated nucleation (PSN) is also observed in the present alloy.