General procedure of failure analysis: Determination of type of fracture II — Lesson 1

This lesson covers the subject of fracture analysis and prevention, focusing on the determination of fracture types. It delves into the mechanisms of dimple fracture, cleavage fracture, and intergranular fracture, explaining how cracks propagate in different materials under various conditions. The lesson also discusses the impact of factors such as grain size, thermal treatment, high-temperature exposure, and environmental factors on fracture types. For instance, it explains how high-strength aluminum, zinc, and magnesium alloys can experience stress corrosion cracking even under atmospheric conditions. The lesson concludes with a discussion on how to determine the causes of intergranular fractures.

Video Highlights

01:16 - Explanation of the growth of incipient cracks and slip band deformation.
04:13 - Explanation of the impact of different loading capabilities on dimple formation.
10:36 - Explanation of the typical features of cleavage facets.
19:58 - Discussion on the different ways in which stress corrosion cracking can occur.
26:56 - Discussion on the impact of grain size on the mechanism of fracture.

Key Takeaways

- Dimple fracture, cleavage fracture, and intergranular fracture are the main types of fractures discussed.
- The propagation of cracks in materials varies depending on the type of fracture and the conditions.
- Factors such as grain size, thermal treatment, high-temperature exposure, and environmental factors significantly impact fracture types.
- High-strength aluminum, zinc, and magnesium alloys can experience stress corrosion cracking even under atmospheric conditions.
- Determining the causes of intergranular fractures involves understanding the presence of poor phases at the grain boundary.