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Aerospace thermal envelope: –196 °C to 1,000 °C

A 500‑cycle thermal ramp from –196 °C (LN₂) to 1,000 °C, performed by the Ramamurty metallurgy bench at NTU Singapore, returned 92.6 % tensile retention for 0.025 mm NP1 wire — a 15‑point improvement over reference NP2 controls.

GTX Research · Aerospace desk21 April 202615 minCC-BY-4.0ScholarlyArticle

1. Setup

Thermal cycling was performed on a Linseis L75 dilatometer calibrated to ASTM E228 with ancillary LN₂ quench station. Each cycle: LN₂ immersion (–196 °C, 120 s) → ambient (30 s) → induction ramp (1,000 °C, 120 s) → ambient (30 s). 500 cycles in total.

Test coupons: 50 mm NP1 wire, 0.025 mm diameter, n = 12. Controls: NP2 equivalent, n = 12. Tensile testing performed at 23 ± 1 °C on Instron 5969 after cycling.

2. Results

Fig. 1 — Tensile retention vs cycle count, NP1 vs NP2.

NP1 retained 92.6 % of baseline ultimate tensile strength after 500 cycles. NP2 retained 77.4 % under identical conditions. The 15‑point gap is explained by sulphur and iron grain‑boundary control in NP1 (NSL Analytical chemistry, < 10 ppm combined S + Fe).

CTE from 25 °C to 1,000 °C: 16.4 × 10⁻⁶ K⁻¹ (NP1), stable within 3 % across the envelope.

3. Applications

The 500‑cycle, full‑envelope qualification brings NP1 wire into scope for: AESA substrate looms, composite‑tooling mandrels, stealth radar‑absorbing‑material (RAM) carriers, and engine‑bay harnesses. Lectromec (USA) performs the downstream aerospace electrical qualification (ISO/IEC 17025 / NASA‑certified) and issues the 20‑year service lifespan determination.

Tensile retention
92.6 %
After 500 cycles, –196 → 1,000 °C.
Envelope
–196 °C to 1,000 °C
Full aerospace operational band.
Service lifespan
20 years
Lectromec (NASA‑certified) determination.
CTE
16.4 × 10⁻⁶ K⁻¹
25 °C to 1,000 °C, NP1 wire.

Sources & references

  1. ASTM International. E228 — Standard Test Method for Linear Thermal Expansion. astm.org
  2. Prof. Upadrasta Ramamurty, NTU Singapore. Thermal‑cycling bench, 2025.
  3. Lectromec. Aerospace electrical qualification, NASA‑certified, 2025.