The Failure Analysis Process: An Overview Debbie Aliya, Aliya Analytical Introduction FAILURE ANALYSIS is a process that is performed in order to determine the causes or factors that have led to an undesired loss of functionality. This Volume primarily addresses failures of components, assemblies, or structures, and its approach is one consistent with the knowledge base of a person trained in materials engineering. The contribution of the materials engineer to the advancement of the scientific foundation of failure analysis has been great in the last few decades. This can be shown by the fact that many people define the causes of failure in a rather binary manner: was the part defective or was it abused? Obviously there are many types of defects, including those that come from a deficient design, poor material, or mistakes in manufacturing. Whether those"defects"exist in a given component that is being subjected to the failure analysis process can often only be determined by someone with a materials background. The reasons for this are related to the fact that many of the"defects"that people are looking for are visible only in a microscope of ome sort. While microscopes may be widely available, the knowledge required to interpret the images is less widely available. The other major type of defects, those related to design issues, may also require the assessment of a materials engineer. This is because many design engineers are not very familiar with the natural variations within a material grade. Evaluation of the adequacy of a material or process specification is often best performed by a materials engineer Thus, materials experts have been in an excellent position to gain experience in the failure analysis process. The advent of more and more powerful and widely available scanning electron microscopes has helped provide a more fact based foundation for opinions that may have been heavily speculative in the past. Some materials engineers have become very experienced in failure analysis. As materials engineers have worked on some very pectacular failures or on failures that have caused great pain and loss, they have been led to ask deeper and broader questions about the causes that lead to failures. In many cases it becomes clear that there is no single cause and no single train of events that lead to a failure. Rather, there are factors that combine at a particular time and place to allow a failure to occur. Sometimes the absence of any single one of the factors may have been enough to prevent the failure. Sometimes, though, it is impossible to determine, at least within the resources allotted for the analysis, whether any single factor was key. If failure analysts are to perform their jobs in a professional manner, they must look beyond the simplistic list of causes of failure that some people still promote. They must keep an open mind and always be willing to get help when beyond their own perience Many beginning practitioners of failure analysis may have their projects defined for them when they are handed a small component to evaluate and, thus, may be able to follow an established procedure for the evaluation This is especially true for someone working within an original equipment manufacturer. If there is someone who has a lot of experience and knowledge of the physical factors that tend to go wrong with the object and an established procedure exists, then a particular analysis may not require extensive pretesting work. However, for the practitioner who works in an independent laboratory or who is looking at a wide variety of components, following a predefined set of instructions for a failure analysis will generally prove to be an inadequate guideline for the investigation. Established"recipe type" procedures are generally inadequate for the more dvanced and broad-minded practitioner as well Although the failure that we are investigating is that of a physical component, assembly, or structure, the failures that lead to such physical failure happen on many levels. In other words, a failure should not be viewed as a single event. It is more useful to view both the failure and the failure analysis as multilevel processes that can be explored in many useful ways. The physical failure-a fracture, an explosion, or component damaged by heat or corrosion-is the most obvious. However, there are always other levels of failures that allow the physical event to happen. For example, even a simple failure whose direct physical cause was an improper hardness value has human factors that allowed the improperly hardened component to be manufactured and used. These human factors are generally very difficult to investigate within a manufacturing organizationThe Failure Analysis Process: An Overview Debbie Aliya, Aliya Analytical Introduction FAILURE ANALYSIS is a process that is performed in order to determine the causes or factors that have led to an undesired loss of functionality. This Volume primarily addresses failures of components, assemblies, or structures, and its approach is one consistent with the knowledge base of a person trained in materials engineering. The contribution of the materials engineer to the advancement of the scientific foundation of failure analysis has been great in the last few decades. This can be shown by the fact that many people define the causes of failure in a rather binary manner: was the part defective or was it abused? Obviously, there are many types of defects, including those that come from a deficient design, poor material, or mistakes in manufacturing. Whether those “defects” exist in a given component that is being subjected to the failure analysis process can often only be determined by someone with a materials background. The reasons for this are related to the fact that many of the “defects” that people are looking for are visible only in a microscope of some sort. While microscopes may be widely available, the knowledge required to interpret the images is less widely available. The other major type of defects, those related to design issues, may also require the assessment of a materials engineer. This is because many design engineers are not very familiar with the natural variations within a material grade. Evaluation of the adequacy of a material or process specification is often best performed by a materials engineer. Thus, materials experts have been in an excellent position to gain experience in the failure analysis process. The advent of more and more powerful and widely available scanning electron microscopes has helped provide a more fact based foundation for opinions that may have been heavily speculative in the past. Some materials engineers have become very experienced in failure analysis. As materials engineers have worked on some very spectacular failures or on failures that have caused great pain and loss, they have been led to ask deeper and broader questions about the causes that lead to failures. In many cases it becomes clear that there is no single cause and no single train of events that lead to a failure. Rather, there are factors that combine at a particular time and place to allow a failure to occur. Sometimes the absence of any single one of the factors may have been enough to prevent the failure. Sometimes, though, it is impossible to determine, at least within the resources allotted for the analysis, whether any single factor was key. If failure analysts are to perform their jobs in a professional manner, they must look beyond the simplistic list of causes of failure that some people still promote. They must keep an open mind and always be willing to get help when beyond their own experience. Many beginning practitioners of failure analysis may have their projects defined for them when they are handed a small component to evaluate and, thus, may be able to follow an established procedure for the evaluation. This is especially true for someone working within an original equipment manufacturer. If there is someone who has a lot of experience and knowledge of the physical factors that tend to go wrong with the object and an established procedure exists, then a particular analysis may not require extensive pretesting work. However, for the practitioner who works in an independent laboratory or who is looking at a wide variety of components, following a predefined set of instructions for a failure analysis will generally prove to be an inadequate guideline for the investigation. Established “recipe type” procedures are generally inadequate for the more advanced and broad-minded practitioner as well. Although the failure that we are investigating is that of a physical component, assembly, or structure, the failures that lead to such physical failure happen on many levels. In other words, a failure should not be viewed as a single event. It is more useful to view both the failure and the failure analysis as multilevel processes that can be explored in many useful ways. The physical failure—a fracture, an explosion, or component damaged by heat or corrosion—is the most obvious. However, there are always other levels of failures that allow the physical event to happen. For example, even a simple failure whose direct physical cause was an improper hardness value has human factors that allowed the improperly hardened component to be manufactured and used. These human factors are generally very difficult to investigate within a manufacturing organization