## 1 Introduction
However, it is commonly found in architected metamaterials with different materials and microstructures that periodic arrangement of struts and nodes make them fail along the particular direction [22; 23]. Consequently, they suffer an obvious reduction of strength under external loads due to the presence of shear bands and deformation localization [23; 24], which indicates the inefficiency and reduced performance in energy absorption applications. To solve this problem, two aspects of approaches have been recently proposed: (a), one is to improve the manufacturing process, such as employing post-manufacture heat treatment [22], or optimizing process parameters [23]; (b), the other is to modify the structural configuration, such as orientation change [25] or beam shape modification [26]. However, the improvement of manufacturing process is so far focused only on metallic materials, and at the cost of strength reduction [22]. Comparatively, structural modification is more effective in improving energy absorption capability at the same time maintaining higher strength, while it is still restricted to the architected metamaterials with perfect periodicity. From another perspective, the failure along particular direction and the formation of shear band in architected metamaterials with perfect periodicity is similar to the slip activity along defined directions and to the rapid stress reduction in single crystals [27; 28]. However, in polycrystals, other features (such as grain boundaries or precipitates) serve as obstacles to strain localization and slip activity [29; 30]. Due to the similarity of mechanical responses between single crystals and periodically-arranged lattice structures, [PERSON] et al. [31] have supposed that hardening principles that similar to those found in polycrystals are applicable to architected metamaterials, and some of them (grain boundary hardening, multi-phase hardening, etc.) have been verified. However, research efforts have not yet been focused on the detailed comparison of the hardening mechanism between metallurgy and architected metamaterials. The similarities and discrepancies of the deformation behavior and the mechanical responses of crystalline materials and architected metamaterials remain unknown. These problems hinder research efforts to solve the \"rapid failure\"problem by changing the periodic arrangements of unit cells, as well as establish a systematic strengthening theory in architected metamaterials of such design. Herein, we limit our attention to the precipitate-type architected metamaterials that mimic the crystallographic microstructures of precipitation-hardened alloys. The architected metamaterials are constructed by repeating a 2D geometry on the out-of-plane direction. In-plane mechanical properties and deformation behavior of these structures under compression are investigated in detail to figure out the effect of such design. The deformation mode and strengthening effect are then compared to those of precipitation-hardened alloys. General disciplines of the similarities and discrepancies between Orowan hardening mechanism and the strengthening effect found in architected metamaterials are summarized, which validates our attempt to integrate metallurgical hardening principles into unit cell design.