CAMT Material Properties & Characterization 1

Question 1

Which material property describes the ratio of stress to strain in the elastic region of a stress-strain curve?

Accepted Answer

Modulus of elasticity (Young's modulus)

Answer

Young's modulus defines the stiffness of a material as the slope of the linear elastic portion of the stress-strain curve.

Question 2

In additive manufacturing, anisotropy of mechanical properties is most commonly caused by:

Accepted Answer

Layered build direction creating directional microstructure

Answer

The layer-by-layer deposition creates a directional microstructure, making properties stronger along certain axes than others.

Question 3

Which test is used to measure the resistance of a material's surface to permanent indentation?

Accepted Answer

Hardness test

Answer

Hardness tests (Rockwell, Brinell, Vickers) measure resistance to surface indentation by a standardized indenter.

Question 4

Porosity in metal AM parts is most problematic because it:

Accepted Answer

Acts as a stress concentrator that reduces fatigue life

Answer

Pores act as stress concentration points that initiate cracks under cyclic loading, significantly reducing fatigue life.

Question 5

Which phenomenon occurs when a polymer AM material absorbs moisture from the environment, affecting print quality?

Accepted Answer

Hygroscopy

Answer

Hygroscopy is the tendency of certain materials to absorb moisture, which can cause bubbling and inconsistent extrusion in FDM printing.

CAMT - Certified Additive Manufacturing Technician Practice Test