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Question

Difficulty: HardCausal Detail Extraction

Read the following technical report on aerospace fastener manufacturing:

During electroplating surface treatments on high-strength alloy bolts, atomic hydrogen diffuses into the crystalline metal lattice as a direct consequence of chemical acid pickling. When these fasteners are subsequently subjected to sustained tensile stress during assembly, the trapped interstitial hydrogen migrates toward regions of microscopic stress concentration. Consequently, atomic hydrogen recombines at sub-surface grain boundaries, generating localized internal pressure that severely reduces material ductility. Unless components undergo immediate post-plating thermal baking to drive out dissolved gases, catastrophic intergranular fracturing can occur abruptly under operational load without prior macroscopic plastic deformation.

Based on the passage, match each manufacturing or operational condition on the left with its directly stated physical consequence on the right.

  • Chemical acid pickling of alloy boltsDiffusion of atomic hydrogen into the crystalline metal lattice
  • Application of sustained tensile stress during assemblyMigration of interstitial hydrogen toward microscopic stress concentration zones
  • Atomic hydrogen recombination at grain boundariesGeneration of localized internal pressure that severely reduces material ductility
  • Omission of post-plating thermal bakingAbrupt catastrophic intergranular fracturing without macroscopic plastic deformation

Answer

Chemical acid pickling pairs with the diffusion of atomic hydrogen into the crystalline lattice; sustained tensile stress pairs with the migration of hydrogen toward stress concentration zones; recombination at grain boundaries pairs with the generation of localized internal pressure reducing ductility; and omitting thermal baking pairs with abrupt intergranular fracturing without plastic deformation.
Each match strictly aligns with explicit causal markers in the text ('direct consequence of', 'When... migrates', 'Consequently... generating', and 'Unless... fracturing can occur'). Every condition on the left corresponds directly and exclusively to its stated immediate physical effect on the right.

Step-by-Step Solution

1
Locate the explicit cause-and-effect statement for chemical acid pickling.
Identified the explicit phrase 'as a direct consequence of chemical acid pickling', which links pickling directly to hydrogen diffusing into the crystalline metal lattice.
Direct retrieval of the initial causal mechanism introduced in the text.
2
Identify the direct effect of applying sustained tensile stress during assembly.
The text links sustained tensile stress during assembly to interstitial hydrogen migrating toward regions of microscopic stress concentration.
Extracting the second sequential causal link in the hydrogen embrittlement chain.
3
Extract the consequence of atomic hydrogen recombination at grain boundaries.
The connective 'Consequently' indicates that recombination generates localized internal pressure that severely reduces ductility.
Pinpointing intermediate material degradation resulting from hydrogen recombination.
4
Determine the outcome when post-plating thermal baking is omitted.
The conditional statement beginning with 'Unless' explicitly ties the failure to bake out dissolved gases to abrupt catastrophic intergranular fracturing under operational load.
Resolving the final conditional causal consequence stated in the passage.

Key Concept

Extracting explicit cause-and-effect relationships and multi-stage causal chains directly from technical prose using explicit textual signals.
Estimated Time:2m 0s
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Topics

Causal Detail Extraction

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