DD6高温合金定向凝固枝晶生长的数值模拟研究_张航

装备环境工程第20卷第12期·20·EQUIPMENT ENVIRONMENTAL ENGINEERING2023年12月不同温度下DD6单晶高温合金的燃气热腐蚀行为研究杨丽媛，张骐，孙志华，刘明，赵明亮（北京航空材料研究院 航空材料先进腐蚀与防护航空科技重点实验室，北京 100095）摘要：目的研究DD6高温合金在650、800、950 ℃等3种典型温度的燃气热腐环境下的耐腐蚀性能。

方法采用X射线衍射（XRD）、扫描电镜（SEM）、能谱仪（EDS）等测试方法，研究不同温度下DD6高温合金的热腐蚀行为。

结果与结论随着温度的升高，合金的腐蚀速率呈逐渐增加的趋势。

当温度为650、800 ℃时，合金的腐蚀速率较小；当温度为950 ℃时，表面腐蚀产物明显剥落，腐蚀程度明显增加。

在650 ℃下，DD6合金的腐蚀层较薄，主要为NiO、Al2O3等氧化物。

在800、950 ℃下，腐蚀层分为2层，外层由2部分构成，最外侧为一薄层NiO和Co3O4等的混合物，次外层为相对疏松的NiO，内层为Al2O3和Cr2O3构成的相对致密的腐蚀层。

腐蚀层下方的基体中，出现了γ'相退化区，并且出现了明显的内硫化现象，加剧了热腐蚀作用。

关键词：DD6；单晶高温合金；燃气热腐蚀；微观形貌；内硫化中图分类号：TG132.3 文献标识码：A 文章编号：1672-9242(2023)12-0020-06DOI：10.7643/ issn.1672-9242.2023.12.003Hot Gas Corrosion Behavior of Single Crystal Superalloy DD6 at Different Temperature YANG Li-yuan, ZHANG Qi, SUN Zhi-hua, LIU Ming, ZHAO Ming-liang(Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material,AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China)ABSTRACT: The work aims to study the corrosion resistance of DD6 super alloy in three typical hot gas corrosion environ-ments at 650 ℃, 800 ℃ and 950 ℃. The corrosion behavior of DD6 super alloy was investigated by X-Ray Diffraction, scan-ning election microscopy and energy dispersive X-ray spectrum (EDS). The hot corrosion rate of alloy increased with the in-crease of temperature. The hot corrosion rates at 650 ℃ and 800 ℃ were relatively low. Significant spallation of corrosion products and obvious corrosion occurred at 950 ℃. The corrosion layer of DD6 alloy at 650 ℃ was relatively thin, mainly composed of oxides such as NiO and Al2O3. The corrosion products were divided into two layers at 800 ℃ and 950 ℃. The outer layer consisted of two parts, the outermost layer was a mixture of a thin layer of NiO and Co3O4, the secondary layer was loose NiO and the inner layer was a relatively dense corrosion layer composed of Al2O3 and Cr2O3. The phase γ' degradation zone appeared in the alloy below the corrosion layer, and there was obvious internal vulcanization phenomenon which acceler-ated the hot corrosion.KEY WORDS: DD6; single crystal super alloy; hot gas corrosion; microstructure; internal vulcanization收稿日期：2023-10-29；修订日期：2023-12-11Received：2023-10-29；Revised：2023-12-11引文格式：杨丽媛, 张骐, 孙志华, 等. 不同温度下DD6单晶高温合金的燃气热腐蚀行为研究[J]. 装备环境工程, 2023, 20(12): 20-25. YANG Li-yuan, ZHANG Qi, SUN Zhi-hua, et al. Hot Gas Corrosion Behavior of Single Crystal Superalloy DD6 at Different Temperature[J]. Equipment Environmental Engineering, 2023, 20(12): 20-25.第20卷第12期杨丽媛，等：不同温度下DD6单晶高温合金的燃气热腐蚀行为研究·21·DD6单晶高温合金具有优异的综合力学性能（拉伸、持久、蠕变）和良好的抗氧化性，目前已广泛应用于航空发动机和燃气轮机关键热端部件[1-8]。

DD6合金1100℃低周疲劳行为张仕朝;李旭东;于慧臣;侯学勤【摘要】The total strain-controlled low cycle fatigue(LCF)behaviors of a single crystal superalloy DD6 at 1100 ℃ for R= -1 and 0. 05 were investigated. The results of LCF tests indicated that the cyclic hardening/softening behavior of the alloy not only has the re-lationship with the microstructure of the material,but also the loading status. The mean stress relaxation occurred under asymmetric straining. The rate of mean stress relaxation increased with the increasing of strain amplitude;when R= -1,the alloy shows tension-compression asymmetry behavior. All the LCF data obtain under various ratios were well correlated by three models for lifetime predic-tion,the precision rates predicted are fallen into the factor of ± 2 tim es scatter band.%研究了1100℃下镍基单晶高温合金DD6不同应变比(R=-1,0.05)下的低周疲劳行为.结果表明:材料的循环软化/硬化行为不仅与材料本身的微观结构有关,还与加载状态有关;平均应变为正时,非对称循环应变控制会产生平均应力松弛现象,且随着应变幅的增大,平均应力松弛速率增大;R=-1时,材料表现出拉压不对称性;采用三种不同的模型对不同应变比下的寿命进行表征,预测精度基本落在±2倍的分散带内.【期刊名称】《航空材料学报》【年(卷),期】2018(038)001【总页数】6页(P95-100)【关键词】单晶高温合金;低周疲劳;拉压不对称性;应力松弛【作者】张仕朝;李旭东;于慧臣;侯学勤【作者单位】中国航发北京航空材料研究院先进高温结构材料重点实验室,北京100095;航空材料检测与评价北京市重点实验室,北京100095;材料检测与评价航空科技重点实验室,北京100095;中国航发北京航空材料研究院先进高温结构材料重点实验室,北京100095;航空材料检测与评价北京市重点实验室,北京100095;材料检测与评价航空科技重点实验室,北京100095;中国航发北京航空材料研究院先进高温结构材料重点实验室,北京100095;航空材料检测与评价北京市重点实验室,北京100095;材料检测与评价航空科技重点实验室,北京100095;中国航发北京航空材料研究院先进高温结构材料重点实验室,北京100095;航空材料检测与评价北京市重点实验室,北京100095;材料检测与评价航空科技重点实验室,北京100095【正文语种】中文【中图分类】TG146.1+5镍基单晶高温合金因其优越的高温抗疲劳和抗蠕变性能，已成为制造航空涡轮发动机热端部件的重要材料。

DD6单晶高温合金振动疲劳性能及断裂机理刘丽玉;高翔宇;杨宪锋;何玉怀【摘要】Room Temperature vibration fatigue S-N curves of single crystal superalloy DD6 with [001] orientation was investigated and room temperature vibration fatigue limit was obtained .The fracture mechanism was studied by OM ,SEM and EBSD .The results show that based on S-N method ,vibra-tion fatigue limit of DD6 single crystal superalloy with [001] orientation is estimated to be around 337 .5M Pa .Vibration fatigue fracture presents single or several {111} octahedral slip planes .SEM observations show that fracture has two regions :fatigue source region and the fatigue crack propaga-tion regions ,the fatigue cracks initiate at the surface or internal defect of the cross-section with the maximumstress ,and exhibits a single source feature ,fatigue crack propagation region exhibits quasi-cleavage fracture ,no typical fatigue striationfeature .Crystal plane slip along {111} is the main de-formation mechanism of RT vibration fatigue fracture of single crystal superalloy DD 6 ,quasi-cleavage propagation plane in fracture and quasi-cleavage patterns in microstructure are the main features of RT vibration fatigue fracture of single crystal superalloy DD 6.%研究[001]取向的DD6单晶高温合金的室温振动疲劳S-N曲线,并获得了其室温振动疲劳极限.利用体视显微镜、扫描电子显微镜、背散射衍射等手段对DD6单晶高温合金振动疲劳断裂机制进行分析.结果表明:采用S-N法估算得到的[001]取向的DD6单晶高温合金室温振动疲劳极限约为337.5M Pa.振动疲劳裂纹断口呈现单个或多个沿{111}晶体学扩展平面组成的形貌特征,断口上分为疲劳源区和疲劳扩展区两个阶段,裂纹在应力最大截面处的表面或内部缺陷处萌生,呈单源特征,疲劳扩展区呈现类解理断裂特征,未出现典型的疲劳条带特征.说明沿{111}晶面滑移是DD6单晶高温合金室温振动疲劳断裂的主要变形机制,断口上的类解理扩展平面以及微观上类解理花样是DD6单晶高温合金室温振动疲劳断裂的主要特征.【期刊名称】《材料工程》【年(卷),期】2018(046)002【总页数】6页(P128-133)【关键词】DD6单晶高温合金;振动疲劳;断裂机理;类解理平面【作者】刘丽玉;高翔宇;杨宪锋;何玉怀【作者单位】中国航发北京航空材料研究院,北京100095;航空材料检测与评价北京市重点实验室,北京100095;材料检测与评价航空科技重点实验室,北京100095;中国航发北京航空材料研究院,北京100095;航空材料检测与评价北京市重点实验室,北京100095;材料检测与评价航空科技重点实验室,北京100095;中国航发北京航空材料研究院,北京100095;航空材料检测与评价北京市重点实验室,北京100095;材料检测与评价航空科技重点实验室,北京100095;中国航发北京航空材料研究院,北京100095;航空材料检测与评价北京市重点实验室,北京100095;材料检测与评价航空科技重点实验室,北京100095【正文语种】中文【中图分类】V241现代航空发动机发展的主要特点是提高涡轮前温度，以有效地改善发动机性能，而涡轮前温度的提高很大程度上取决于涡轮叶片的承温能力[1]。

热等静压对第二代单晶高温合金DD6显微组织和力学性能的影响郭会明;赵云松;郑帅;许剑伟;张剑;骆宇时;董建新【摘要】Effects of the hot‐isostatic pressing (HIP) temperature(1280 ,1300 ,1320℃) on microstruc‐tures and mechanical properties of a second generation single crystal superalloy DD 6 were investiga‐ted .T he results show that the HIP treatment significantly decrease the cast porosity number of DD 6 compared with standard treatedspecimens .Especially ,the cast porosity volume fraction is deceased from 0 .31% to 0 .04% after the HIP treatment of 1300℃/100MPa ,4h .The cast eutectic volume fractions are remarkably reduced with increasing HIP temperature .The HIP treatments nearly un‐changed the creep lives ,While they greatly promote the low cycle fatigue lives .The elimination of cast microspores using the HIP treatment of 1300℃/100M Pa ,4h result in the inhibition of crack initi‐ation during fatigue and improve the low cycle fatigue lives one order of magnitude larger than that af‐ter standard heat treatment .%通过1280，1300℃和1320℃3个温度的热等静压实验，对比分析热等静压对第二代单晶高温合金DD6显微组织和力学性能的影响。

不同使用温度下DD6单晶高温合金的组织演变行为史振学;刘世忠;熊继春;李嘉荣【摘要】The second generation single crystal superalloy DD6 after standard heat treatment was heat-treated at 1100, 1150, 1200, 1250, 1300 and 1320℃ for 1 h, respectively, and was then air cooled. The microstructures of the alloy heat-treated at different temperatures were investigated by SEM. The microstructure evolution mechanism of the alloy was estimat using JMatPro software and DSC.The results show that the size ofγ′ phase slightly increases after DD6 super alloy heat-treatment at 1100, 1150 and 1200℃. The size ofγ′ phase increases apparently and its size distribution is very uneven after heat treatment at 1250℃. The small part ofγ′ phase has serratedγ′/γ phase surface as a result of incomplete solution and the irr egular smallγ′ phase is majorafter heat-treatment at 1300℃. While the irregular smallγ′phase precipitates again, followed complete solution after heat-treatment at 1320℃. The size, shape and volume fraction ofγ′ phase vary with the heat treatment temperatu res because it grows, dissolves or precipitates again. The volume fraction ofγ′ phase decreasesto different degrees after heat-treatment at different temperatures except 1100℃. There is no fine secondγ′ phase in theγ matrix channel of the alloy after standard heat-treatment and heat-treatment at 1320℃. But the fine secondγ′ phase precipitates in theγ matrix channel after heat-treatment at temperature range of 1100−1300℃. Different microstructures are obtained after heat-treatment at differenttemperatures, which indicates that the using temperature has obvious effect on the microstructure of the alloy.%对完全热处理后的第二代单晶高温合金DD6分别在1100、1150、1200、1250、1300和1320℃温度下保温1 h 后再进行空冷处理。

单晶铸造是定向凝固中的一个特例…由一个柱状晶构成的铸件即单晶！！绪论航空发动机涡轮叶片的运行经验表明，大多数裂纹都是沿着垂直于叶片主应力方向的晶粒间界即横向晶界上产生和发展的。

因此消除这种横向晶界，则可大大提高叶片抗裂纹生长能力。

定向凝固就是基于这种设想对叶片铸件的凝固过程进行控制，以获得平行干叶片轴向的柱状晶粒组织。

柱状晶之间只有纵向晶界而无横向品界，这就是定向凝固的柱晶叶片，如果采取某些措施，只允许有一个晶粒成长的柱晶，从面消除了一切晶界，这就是单晶叶片。

由于定向凝固技术用于真空熔铸高温合金涡轮叶片，航空发动机的材料和性能有了极大的提高，特别是单晶叶片的性能和使用寿命比普通精铸叶片提高了许多倍，因此自70年代初期，定向凝固高温合金涡轮叶片开始应用以来，世界各先进的军用及民用航空发动机都普遍采用定向凝固或单晶铸造叶片。

1.定向凝固1.1定向凝固原理进行定向凝固以得到连续完整的柱状晶组织，必须满足以下两基本条件:(l)在整个凝固过程中，铸件的固一液相界面上的热流应保持单一方向流出，使成长晶体的凝固界面沿一个方向推进;(2)结晶前沿区域内必须维持正向温度梯度，以阻止其他新晶核的形成。

1.1.1定向凝固过程定向凝固时合金熔液注入壳型，首先同水冷底板相遇，于是靠近板面的那一层合金熔液迅速冷至结晶温度以下而开始结晶，但此时形成的晶粒，其位向是混乱的，各个方向都有。

在随后的凝固进行过程中，由于热流是通过已结晶的固体金属合金有方向性地向冷却板散热，且结晶前沿是正向温度梯度，根据立方晶系的金属及合金（Ni、Fe、Co等及其高温合金）在结晶过程中晶体<100>是择优取向，长大速度最快，从而那些具有<100>方向的晶粒择优长大，而将其他方向的晶粒排挤掉。

只要上述定向凝固条件保持不变，取向为<100>的柱状晶继续生长，直到整个叶片，如图1-1所示。

散热方向正温度梯度图1-1 晶体定向生长示意图1.1.2凝固参数定向凝固的结晶组织与凝固参数即温度梯度G和凝固成长速率R有密切关系。