Milestone map
Milestone map
3 milestones
Define Design Requirements and Material Property Targets
1–2 weeks (3–4 hrs/week)
Identify the component or structure that requires material selection — a structural bracket, heat exchanger tube, gear, housing, or similar. Define the design requirements: mechanical loads (stress, fatigue), thermal environment (operating temperature range), chemical exposure (corrosive media), manufacturing constraints, and cost targets. Translate these into quantitative material property targets (minimum yield strength, maximum thermal conductivity, maximum density, etc). Clear property targets prevent the most common selection error: choosing a material that meets some requirements while failing others.
Proof required
Submit your requirements document (≥500 words): the component description, service conditions (loads, temperatures, chemical exposure), manufacturing constraints, and a table of quantitative material property targets with justification for each.
What gets checked
- Property targets are quantitative — 'minimum yield strength ≥ 250 MPa' not 'strong enough'
- At least four distinct property targets are stated covering mechanical, thermal, chemical, and cost/manufacturing requirements
- Each target is justified by reference to the service condition that drives it
Common mistakes
- Defining only mechanical requirements while ignoring cost, manufacturability, or environmental exposure — all four categories must be addressed
- Setting property targets that are too tight (nothing can meet them) or too loose (many unsuitable materials pass) — calibrate against known materials first
Resources
Foundationstart here
Depthgo deeper
What a verifier looks for
- Confirm property targets are quantitative with units — minimum tensile strength in MPa, maximum operating temperature in °C, etc.
- Confirm at least four distinct property categories are addressed (mechanical, thermal, chemical/environmental, cost/manufacturing).
- Confirm each target is justified by the service condition driving it — not stated as arbitrary numbers.
Screen and Compare Candidate Materials
2–3 weeks (3–4 hrs/week)
Apply the Ashby selection method: use property charts or a weighted ranking matrix to screen the entire material space down to ≤5 candidates that meet all hard constraints. Compare candidates against the full property target set. Use free material property databases (MatWeb, Matweb Lite, NIST MML, or Granta free resources) to obtain property data. Document every screening step — which constraint eliminated which material families.
Proof required
Submit your screening document: property chart or weighted matrix showing all candidates, the ≤5 survivors with their key property values sourced from named databases, and a table comparing survivors against all property targets.
What gets checked
- Screening is documented step by step — which property constraint eliminated which material class
- Property values for all candidates are cited from named free databases (MatWeb, NIST, or equivalent) — not from memory
- ≤5 survivors all meet every hard constraint — no survivor fails any must-meet criterion
Common mistakes
- Jumping straight to a preferred material without screening the full material space — the point of the Ashby method is to prevent confirmation bias
- Using generic property ranges without citing specific databases — property values must be traceable to a source
Resources
Foundationstart here
Depthgo deeper
What a verifier looks for
- Confirm screening eliminates material families systematically using the stated property targets — not personal preference.
- Confirm property values are sourced from named databases — MatWeb, NIST, or equivalent; not from unattributed memory.
- Confirm all ≤5 survivors meet every hard constraint — flag any survivor that fails a must-meet criterion.
Select, Justify, and Report the Recommendation
2–3 weeks (2–3 hrs/week)
Choose the preferred material from the ≤5 candidates using a weighted scoring matrix that includes all property targets plus secondary factors (availability, recyclability, specific manufacturing process compatibility). Write a materials selection report documenting the method, screening process, comparison, and recommendation. Present the recommendation to a reviewer with mechanical or materials engineering experience and respond to Q&A on why alternatives were rejected.
Proof required
Submit your materials selection report (≥1,500 words + tables) and a review record: reviewer name, role, ≥3 challenge questions asked, and your responses.
What gets checked
- Weighted scoring matrix applies stated weightings consistently across all candidates — not reverse-engineered to favour the answer
- Report explains why each rejected candidate was inferior — not just why the chosen material is good
- Reviewer challenged at least one choice and the submitter responded with engineering reasoning, not just description
Common mistakes
- Recommending a material without acknowledging its trade-offs — every material has limitations; the report must name them
- Reviewer is not in mechanical or materials engineering — challenge questions must probe whether the property trade-offs are sound
Resources
Foundationstart here
Depthgo deeper
What a verifier looks for
- Engineering Design Triad check: M1–M3 together produce a design artifact (property targets document), an analysis artifact (screening matrix + weighted comparison table), and a documentation artifact (materials selection report + review record) — confirm all three types are present.
- Weighted scoring matrix must state weightings before scoring — confirm weightings appear in the document before scores are applied.
- Report must name trade-offs of the chosen material — not only its advantages.
- Reviewer must have mechanical or materials engineering experience — peer review without domain expertise does not meet the standard.
- The Proof Accessibility Rule applies — MatWeb (free), NIST (free), ASM free resources, and Granta free educational materials are all accessible without institutional license.
Part of