田长生
,
王明升
,
侯铁翠
,
党新安
金属学报
利用高温金相显微镜动态观察了GH169合金在疲劳/蠕变复合作用下的变形和断裂过程。结果表明,疲劳/蠕变复合作用下的变形方式有晶内滑移、孪生和晶界滑动,其失效方式因显微组织而不同。沿晶裂纹源于晶界滑动在三叉点处产生的W型裂纹和晶界局部形变区,其扩展机制为空洞的形核、聚集长大和相互连接;穿晶裂纹源于晶内形变损伤区,其扩展机制为沿滑移面的剪切断裂。
关键词:
GH169合金
,
deformation
,
fracture
,
superalloy GH169
Ping YANG
金属学报(英文版)
Experiments show that special processing techniques such as asymmetrical rolling (ASR), equal channel angular pressing (ECAP) and equal channel angular rolling (ECAR) can weaken the basal texture of the magnesium alloys and therefore improve their plasticity. However, the deformation mechanisms related are different. In this paper, we determine the deformation mechanisms activated during ASR, ECAP and ECAR by calculation of orientation factors. Analysis shows that during ASR the shear stress σ13 on the rolling plane of the samples obviously weakens the basal slip and tension twinning that all produce basal texture and improve plasticity due to the promotion of tilt basal texture. During ECAP the shear stress σs on the intersecting plane of two channels promotes tension twinning in the basal
oriented grains, whereas under ECAR the shear stress σ13 induced by roller friction on the rolling plane produces the shear stress σs on the intersection plane of the two channels that also promotes tension twinning. Although the shear strain is lower in ECAR than in ECAP, the channel clearance in ECAR facilitates tension twinning.
关键词:
Magnesium
,
asymmetrical rolling
,
equal channel angular pressing
,
equal channel angular rolling
,
deformation
张海燕张士宏程明
金属学报
针对Inconel 718合金的Delta工艺, 采用金相显微镜、扫描电镜和定量X射线衍射技术研究了变形温度为950℃、应变速率为0.005 s-1的等温压缩变形中δ相的演变机制. 结果表明: 在变形前的加热和保温阶段, 时效处理过程中晶内析出的颗粒/短棒状δ相全部溶解消失, δ相含量由8.14%降低为7.05%; 在变形过程中δ相发生了溶解, 含量由7.05%进一步降低为5.14%; 由于变形断裂和溶解断裂的综合作用, 片层/长针状δ相发生球化, 由片层/长针状δ相转变为颗粒/短棒状δ相; 在变形量最大的芯部, 片层/长针状δ相全部消失, 颗粒/短棒状δ相分布于晶内与晶界.
关键词:
Inconel 718合金
,
Delta process
,
δ phase
,
deformation
,
spheroidization
TIAN Changsheng WANG Minsheng HOU Tiecui DANG Xin'an Northwestern Polytechnical University.Xi'an
,
China Associate Professor
,
Department of Materials Science and Engineering
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China
金属学报(英文版)
In Situ observation of deformation and fracture for superalloy GH169 under combined fatigue-creep action is made by using high temperature metalloscope,it is shown that under the test conditions the deformution takes place by merely of slipping,twinning and grain houndary sliding,and the mode of failure depends on the microstructure of specimen. lntergranular cracks arise.from W-type voids produced by the stress concentration at triple point which could not be relaxed by the interior deformation of grains and the local deformathm region along grain bounaries.And the crack propagation mechanism is the nucleation,growth and linkage of carities at the grain boundaries.Transgranular cracks form from deformatiom damages within the grain,and its propagation mechanism is shear rupture along the slip phme.
关键词:
combined fatigue-creep action
,
null
,
null
,
null
岳崇锋
,
江社明
,
刘昕
,
王贺贺
,
张启富
,
曲选辉
材料热处理学报
对成形后镀层脱落的热镀锌钢板镀层组织进行了观察,从抑制层形成机制、热浸镀工艺等方面对镀层脱落的原因进行解析.结果表明,镀层发生脱落原因是由于基板表面抑制层不完整,发生铁锌合金反应生成脆性的铁锌合金相,在变形过程中,镀层从铁锌合金相处破坏并产生剥离脱落.建议通过优化以下关键工艺以提高产品质量:提高带钢表面清洁度、严格控制锌液中铝含量、合理控制热浸镀工艺等.经过以上工艺优化与严格控制,最终得到了抑制层连续致密的合格镀锌板产品.
关键词:
热镀锌板
,
脱落
,
抑制层
,
变形
