Hydrostatic cyclic expansion extrusion (HCEE) process at elevated temperatures is proposed as a method for processing less deformable materials such as magnesium and for producing long ultrafine-grained rods. In the HCEE process at elevated temperatures, high-pressure molten linear low-density polyethylene (LLDPE) was used as a fluid to eliminate frictional forces. To study the capability of the process, AM60 magnesium rods were processed and the properties were investigated. The mechanical properties were found to improve significantly after the HCEE process. The yield and ultimate strengths increased from initial values of 138 and 221 MPa to 212 and 317 MPa, respectively. Moreover, the elongation was enhanced due to the refined grains and the existence of high hydrostatic pressure. Furthermore, the microhardness was increased from HV 55.0 to HV 72.5. The microstructural analysis revealed that ultrafine-grained structure could be produced by the HCEE process. Moreover, the size of the particles decreased, and these particles thoroughly scattered between the grains. Finite element analysis showed that the HCEE was independent of the length of the sample, which makes the process suitable for industrial applications.

提出了在高温下的静液压循环膨胀挤压（HCEE）工艺，该工艺用于加工变形较小的材料（例如镁）和生产长超细晶粒棒材。在高温下的HCEE工艺中，高压熔融线性低密度聚乙烯（LLDPE）被用作消除摩擦力的流体。为了研究该工艺的能力，对AM60镁棒进行了加工并研究了其性能。在HCEE工艺后，发现机械性能显着提高。屈服强度和极限强度分别从初始值138和221 MPa增加到212和317 MPa。此外，由于晶粒细化和高静水压力的存在，伸长率得以提高。此外，显微硬度比HV 55高。0至HV 72.5。微观结构分析表明，可以通过HCEE工艺生产超细晶粒结构。此外，颗粒的尺寸减小，并且这些颗粒在颗粒之间充分散布。有限元分析表明，HCEE与样品的长度无关，这使该方法适合工业应用。