API 571 Certification (Corrosion & Materials) Practice Test

What type of materials can be affected by liquid metal embrittlement?

1. Only high-strength steels

2. Carbon and low-alloy steels

3. Plastic materials

4. Cs, LAS, and various alloys

The correct answer is: Cs, LAS, and various alloys

Liquid metal embrittlement is a phenomenon where certain materials become brittle upon exposure to a liquid metal, leading to a loss of mechanical properties such as ductility and toughness. This process typically involves the interaction between the liquid metal and susceptible materials at an elevated temperature or during a specific service condition. The correct answer identifies the materials known to be affected by this type of embrittlement, specifically mentioning "Cs" (which could refer to certain types of carbon steels), "LAS" (likely referring to liquid aluminum-silicon alloys), and various other alloys. These materials well represent examples that have been documented in various studies and field observations as being susceptible to liquid metal embrittlement, especially when they are subjected to stress in the presence of certain liquid metals such as aluminum or mercury. In contrast, high-strength steels alone do not encapsulate the broad range of materials impacted by this phenomenon, which includes different types of alloys and steels beyond just the high-strength category. Additionally, carbon and low-alloy steels are indeed at risk, but they do not encompass the full spectrum indicated in the correct answer. Plastic materials are generally not affected by liquid metal embrittlement as this issue primarily pertains to metallic materials rather than polymers or their derivatives.