CAMT Material Properties & Characterization 2

Question 1

Which characterization technique uses X-rays to determine the crystal structure and phase composition of a metal AM part?

Accepted Answer

X-ray diffraction (XRD)

Answer

Scanning electron microscopy (SEM)

Answer

Energy-dispersive X-ray spectroscopy (EDS)

Answer

Optical profilometry

Question 2

Residual stress in metal AM parts is primarily caused by:

Accepted Answer

Rapid thermal cycling and non-uniform temperature gradients during solidification

Answer

Slow cooling rates during build

Answer

Excessive powder layer thickness

Answer

Low laser power settings

Question 3

The tensile strength of a FDM part is generally highest when the applied load is oriented:

Accepted Answer

Parallel to the build layers (XY-direction)

Answer

Perpendicular to the build layers (Z-direction)

Answer

At a 45-degree angle to the build layers

Answer

Direction has no effect on FDM parts

Question 4

Which material characterization method uses a focused electron beam to image surface morphology at high magnification?

Accepted Answer

Scanning electron microscopy (SEM)

Answer

Coordinate measuring machine (CMM)

Answer

Differential scanning calorimetry (DSC)

Answer

Computed tomography (CT) scanning

Question 5

Differential Scanning Calorimetry (DSC) is used in AM material characterization to measure:

Accepted Answer

Thermal transitions such as melting point, crystallization, and Tg

Answer

Surface roughness of the part

Answer

Dimensional accuracy of the printed part

Answer

Electrical resistance of the material

Question 6

Titanium alloys are widely used in metal AM for aerospace applications primarily because of their:

Accepted Answer

High strength-to-weight ratio and excellent corrosion resistance

Answer

Low melting point and ease of processing

Answer

Low cost compared to steel

Answer

High electrical conductivity

Question 7

In SLS (selective laser sintering) of nylons, the 'refresh rate' of powder refers to:

Accepted Answer

The ratio of new powder mixed with recycled powder to maintain consistent material properties

Answer

How often the laser is recalibrated

Answer

The speed at which new layers are deposited

Answer

The frequency of bed temperature measurements