Processing and Manufacturing Flashcards

Chemical vapor deposition (CVD) is used in materials processing to:

Answer: Deposit thin solid films from gaseous precursors onto a substrate

CVD involves chemical reactions of gaseous precursors at or near a heated substrate surface, depositing a solid thin film with excellent thickness uniformity.

The main purpose of a Sendzimir (Z-mill) rolling configuration is to:

Answer: Allow rolling of hard, thin strips using small-diameter work rolls backed by many support rolls

Z-mills use a cluster of backup rolls to support small-diameter work rolls, enabling rolling of hard alloys (stainless steel, titanium) into thin strip with high rolling forces.

Forging produces parts with superior mechanical properties compared to casting primarily because:

Answer: It refines grain structure and aligns grain flow with part geometry

Forging aligns metal grains along the part geometry (grain flow), refines grain size, and eliminates casting defects, resulting in superior strength, toughness, and fatigue resistance.

In welding metallurgy, the heat-affected zone (HAZ) is the region:

Answer: Adjacent to the weld that was not melted but experienced microstructural changes due to heat

The HAZ is the base metal region that did not melt but reached temperatures high enough to alter its microstructure, often resulting in grain growth or property changes.

Physical vapor deposition (PVD) techniques such as sputtering differ from CVD primarily in that PVD:

Answer: Deposits material from a solid or liquid source without chemical reactions in the vapor phase

PVD physically converts a solid or liquid source material into vapor by sputtering or evaporation and deposits it on a substrate without gas-phase chemical reactions.

A key challenge unique to additive manufacturing (AM) metal parts produced by selective laser melting (SLM) is:

Answer: High residual stresses and anisotropic microstructure from rapid solidification

Rapid, directional solidification in SLM creates columnar grain structures and high residual stresses that require post-processing such as stress relief annealing or HIP to achieve isotropic properties.