Higher strength and higher ductility are desirable for structural materials. However, ultrastrong alloys inevitably show decreased strain-hardening capacity, limiting their uniform elongation. We present a supranano (<10 nanometers) and short-range ordering design for grain interiors and grain boundary regions, respectively, in fine-grained alloys based on vanadium, cobalt, and nickel, with additions of tungsten, copper, aluminum, and boron. The pronounced grain boundary-related strengthening and ductilization mechanism is realized through segregation of the short-range ordering near the grain boundary. Furthermore, the supranano ordering with a larger size has an enhanced pinning effect for dislocations and stacking faults, multiplied and accumulated in grain interiors during plastic deformation. These mechanisms promote continuously increased flow stress until fracture of the alloy at 10% strain with 2.6-gigapascal tensile stress.

Printed circuit heat exchangers (PCHE) are designed to improve heat recovery and energy saving in supercritical CO₂ (S-CO₂) power cycles. In the current study, a modified channel PCHE is proposed based on the regular straight channel and a zigzag channel. The thermal–hydraulic performance of four different types of PCHE is numerically investigated and the methods are verified by both experimental and numerical results. The numerical results are presented for a Reynolds number based on the inlet conditions between 5 000 and 25 000. From the numerical results, the local pressure loss and local heat transfer coefficients are analyzed and discussed. Subsequently, the global Nusselt number and Fanning friction coefficients are discussed. It is found that the inserted straight section contributes to uniform flow, resulted in significant pressure loss reduction with a slight decrease in heat transfer. The modified channel can reduce the Fanning friction coefficient by 33.1%-84.7% while the global Nusselt number reduction is about 3.6%-30.3%. This leads to a maximum performance evaluation criterion (PEC) enhancement of 45.9%.