Abstract Spherical and uniform CuAlMn shape memory foams (SMFs) with quasi-oligocrystalline microstructure and various foam structures were manufactured by the silica-gel beads infiltration method. The strut architecture was quantitatively characterized by strut node size N, strut length L and L/N, and the oligocrystalline degree of foams was characterized by grain size d over N (d/N) for the first time. d/N is found to increase linearly with L/N due to the constricted effect of complex strut architecture on two-dimensional grain growth. The coupling effect of strut sizes and oligocrystalline degree on properties of the SMFs was explored. Too thin struts (smaller N) result in higher quenching rate and consequently more quenched-in vacancies, hindering the thermal-induced martensitic transformation and low-amplitude martensite damping. The peak damping becomes more dependent on d/N and tends to increase with increasing d/N, while the high-amplitude martensite damping improves linearly with d/N. The compression recovery strain also increases linearly with d/N under certain porosity, although higher porosity tends to compromise the favorable effect of higher d/N. The results demonstrate that higher d/N, which corresponds to higher oligocrystalline degree and lower grain constraints, favors the boundary mobility and martensite accommodation and thus improves the damping and compression recovery properties of Cu-based SMFs.

中文翻译：

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通过调整支柱结构实现高低结晶度以提高球形多孔 CuAlMn SMA 的阻尼和机械性能

摘要 采用硅胶珠渗透法制备了具有准低晶微观结构和各种泡沫结构的球形均匀CuAlMn形状记忆泡沫（SMFs）。支撑结构通过支撑节点尺寸N、支撑长度L和L/N定量表征，泡沫的低结晶度首次通过N上的晶粒尺寸d(d/N)表征。由于复杂的支柱结构对二维晶粒生长的限制作用，发现 d/N 随 L/N 线性增加。研究了支柱尺寸和低结晶度对 SMF 性能的耦合效应。太细的支柱（较小的 N）会导致更高的淬火速率，从而导致更多的淬火空位，阻碍热致马氏体转变和低振幅马氏体阻尼。峰值阻尼变得更加依赖于 d/N，并且随着 d/N 的增加趋于增加，而高振幅马氏体阻尼随着 d/N 线性提高。在一定孔隙率下，压缩恢复应变也随 d/N 线性增加，尽管较高的孔隙率往往会损害较高 d/N 的有利效果。结果表明，较高的 d/N 对应于较高的低晶度和较低的晶粒约束，有利于边界迁移率和马氏体适应，从而提高了 Cu 基 SMF 的阻尼和压缩恢复性能。尽管较高的孔隙率往往会损害较高 d/N 的有利效果。结果表明，较高的 d/N 对应于较高的低晶度和较低的晶粒约束，有利于边界迁移率和马氏体适应，从而提高了 Cu 基 SMF 的阻尼和压缩恢复性能。尽管较高的孔隙率往往会损害较高 d/N 的有利效果。结果表明，较高的 d/N 对应于较高的低晶度和较低的晶粒约束，有利于边界迁移率和马氏体适应，从而提高了 Cu 基 SMF 的阻尼和压缩恢复性能。