The Effects of Local Texture and Microstructure on Deformation Mechanism in IN 713C Alloy

IN 713C合金局部织构和显微组织对变形机制的影响

• 批准号: EP/L014572/1
• 负责人: Soran Birosca
• 金额: $ 12.55万
• 依托单位: Swansea University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FL014572%2F1
• 关键词: Effects; Local; Texture; Microstructure; Deformation

The turbocharger is an essential part of a modern diesel engine. The turbine wheel is a key component in the turbocharger and it should be designed to sustain at high temperatures and high rotational speeds during the hostile operating conditions and strenuous duty cycles. Mainly the material used in the turbine wheel is Inconel 713C which is a precipitation hardenable, nickel- chromium base cast alloy. The turbocharger manufactures' requirements imposed on this cast alloy is high as it should includes high fatigue and creep resistance at high temperatures as well as resistance to corrosion in a media containing products of fuel combustion. However, the turbine wheel blades are thermally and mechanically loaded during the operation of the turbocharger that can lead to material failures. With the objective to design safe components and improve fuel consumption, it is necessary to understand the failure mechanisms of the employed materials under these complex loadings. Different failure modes reported in literature, but the two most prominent turbine wheel failure modes are Low Cycle Fatigue (LCF) and High Cycle Fatigue (HCF). In general, there is uncertainty in literature about the exact influence of individual microstructure parameters including porosity, inclusions, grain orientation and slip activity on fatigue life of IN 713C alloy. In a complex system such as cast IN 713C alloy, these parameters should be identified and quantified. This needs complete description of the microstructure and microtexture of the alloys prior and post mechanical testing using various microanalytical tools including HR-SEM, HR-EBSD, EDX, X-ray micro-tomography as it suggested in this proposed study. Conventionally, the crack initiation and propagation during tension, creep and fatigue have always been correlated to some prominent microstructural features such as porosity, inclusions, voids, second phase particle, oxidation and surface conditions in most structure/property relationship studies. However, in a non-homogenous cast microstructure, the role of local zones/regions became very critical in materials performance and integrity. These local regions contain different grain/grain boundary distributions and local textures that create various microstructure/microtexture clusters that can promote/trigger crack initiation and provide fast crack propagation in some specific locations within the material. In this proposed study, along with defect distributions and surface condition of the alloy, other microstructure features including grain orientations, local/micro/macro/meso texture, strain distribution and grain boundary geometry/characteristics will be the focal points in understanding fracture mechanics, failure and deformation mechanisms. The aim of this study is to quantify and discriminate exact microstructural parameters that produced dissimilar crack characteristics in various zone/regions within a cast microstructure. Uniquely, here the parameters that caused crack formation at the surface will be quantified and compared with subsurface cracks and cracking in the bulk materials i.e., away from surface, edges and corners. Moreover, the crack formation in the absence of any microstructural defects will be characterised against the cracks formed in the vicinity of pores and inclusions. Identifying these microstructural parameters is fundamental in understanding the crack initiation and propagation correlation with microstructure and microtexture in cast alloys used at critical high temperature applications. Detailed investigation will be carried out in order to find exact interactions of the crack path, undulation and bifurcation with microtexture clusters that contain different strain/stress accumulations within the material. In this proposed study, in order to validate correlations between microstructure and crystallographic texture (local and global) with crack characteristic various micro-analytical tool will be employed.

涡轮增压器是现代柴油机的重要组成部分。涡轮机叶轮是涡轮增压器中的关键部件，并且其应被设计成在恶劣的操作条件和剧烈的工作循环期间维持高温和高转速。涡轮机叶轮中使用的材料主要是Inconel 713 C，其是可沉淀硬化的镍铬基铸造合金。涡轮增压器制造商对这种铸造合金的要求很高，因为它应该包括在高温下的高抗疲劳性和抗蠕变性以及在含有燃料燃烧产物的介质中的耐腐蚀性。然而，涡轮机轮叶片在涡轮增压器的操作期间受到热负荷和机械负荷，这可能导致材料失效。为了设计安全的部件和改善燃料消耗，有必要了解所用材料在这些复杂载荷下的失效机制。文献中报道了不同的失效模式，但两种最突出的涡轮机叶轮失效模式是低周疲劳（LCF）和高周疲劳（HCF）。一般而言，文献中关于单个微观结构参数（包括孔隙率、夹杂物、晶粒取向和滑移活动）对IN 713 C合金疲劳寿命的确切影响存在不确定性。在复杂的系统中，如铸造IN 713 C合金，这些参数应该被识别和量化。这需要使用各种微观分析工具，包括HR-SEM，HR-EBSD，EDX，X射线显微断层扫描，如本研究所建议的那样，在机械测试之前和之后对合金的微观结构和微观织构进行完整的描述。传统上，在拉伸、蠕变和疲劳过程中的裂纹萌生和扩展总是与一些突出的微观结构特征相关，如孔隙、夹杂物、空隙、第二相颗粒、氧化和表面条件。然而，在非均匀铸造微观结构中，局部区域/区域的作用在材料性能和完整性中变得非常关键。这些局部区域包含不同的晶粒/晶界分布和局部纹理，其产生各种微结构/微纹理簇，其可以促进/触发裂纹萌生并在材料内的一些特定位置提供快速裂纹扩展。在这项拟议的研究中，沿着缺陷分布和合金的表面状况，其他微观结构特征，包括晶粒取向，局部/微观/宏观/介观织构，应变分布和晶界几何形状/特性将是理解断裂力学，失效和变形机制的重点。本研究的目的是量化和歧视精确的微观结构参数，产生不同的裂纹特性在不同的区/区域内的铸造微观结构。独特的是，在这里，导致表面处裂纹形成的参数将被量化，并与表面下裂纹和散装材料中的裂纹进行比较，即，远离表面、边缘和角落。此外，在不存在任何微观结构缺陷的情况下的裂纹形成将与在孔隙和夹杂物附近形成的裂纹相比较。识别这些微观结构参数是理解裂纹萌生和扩展与在临界高温应用中使用的铸造合金中的微观结构和微观织构的相关性的基础。将进行详细的调查，以找到确切的相互作用的裂纹路径，起伏和分叉与微观纹理集群，包含不同的应变/应力积累的材料。在这项拟议的研究中，为了验证微观结构和晶体学织构（局部和全局）与裂纹特性之间的相关性，将采用各种微观分析工具。

项目成果

The deformation behaviour of hard and soft grains in RR1000 nickel-based superalloy

• DOI: 10.1088/1757-899x/82/1/012033
• 发表时间: 2015
• 期刊: IOP Conference Series: Materials Science and Engineering
• 作者: S. Birosca

MSc Thesis: An Investigation into the Deformation Mechanism of IN713C Nickel Based Superalloy during Small Punch Test

硕士论文：IN713C镍基高温合金小冲头变形机理研究

• 发表时间: 2014
• 作者: Hasan Alshehri

Deformation mechanisms of IN713C nickel based superalloy during Small Punch Testing

• DOI: 10.1016/j.msea.2015.10.056
• 发表时间: 2016
• 期刊: Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
• 影响因子: 6.4
• 作者: M. Coleman;H. Alshehri;R. Banik;W. Harrison;S. Birosca