WC-Co hardmetals are popular tool materials, which are used in applications such as metal milling or turning. In these applications, elevated temperatures occur in the tools during the machining process, although they are also cooled. This results in a complex interaction of thermal and mechanical loads in the tools. Within this current work, a strain asymmetry of a WC-10 wt% Co hardmetal after tensile and compression uniaxial step-loading creep tests is described. Two types of tests were performed: Firstly, specimens were deformed to certain strain limits at 700 °C and 800 °C. Strain asymmetry was observed for tensile and compression stresses above 600 MPa at 700 °C and above 250 MPa at 800 °C. In the second type of test, the specimens were stepwise loaded up to a stress of 300 MPa under tensile and compressive load at 800 °C. The aim of test 2 was to identify the physical reason for the strain asymmetry from the first tests at 800 °C. The material's microstructure was analyzed for the specimens from test 2 by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The influence of the loading type was analyzed with regard to damage development and deformation behaviour of the WC- and Co-phase. SEM images showed that the faster increase in strain over time under tensile than under compressive loading was caused by the formation of cavities at WC-WC interfaces and at WC-Co phase boundaries. Due to the larger number of observed microdefects under tension than under compression, it was assumed that this was the physical reason for the strain asymmetry. In addition, EBSD data showed that during the compression and tension creep tests, the fcc Co-phase was partially transformed into the hcp Co-phase.

WC-Co硬质合金是流行的工具材料，用于金属铣削或车削等应用中。在这些应用中，尽管它们也被冷却，但在加工过程中工具中仍会出现高温。这导致工具中热负荷和机械负荷的复杂相互作用。在当前的工作范围内，描述了拉伸和压缩单轴逐步加载蠕变测试后WC-10 wt％Co硬质合金的应变不对称性。进行了两种类型的测试：首先，将样品在700°C和800°C下变形至一定的应变极限。对于在700°C时600 MPa以上和在800°C时250 MPa以上的拉伸应力和压缩应力，观察到应变不对称性。在第二种类型的测试中，在800°C的拉伸和压缩载荷下，将样品逐步加载到300 MPa的应力。测试2的目的是从800°C的第一次测试中找出导致应变不对称的物理原因。通过扫描电子显微镜（SEM）和电子背散射衍射（EBSD）分析了测试2中样品的材料微观结构。分析了载荷类型对WC相和Co相的损伤发展和变形行为的影响。SEM图像表明，在拉伸下，应变随时间的增长比在压缩负载下更快。这是由于在WC-WC界面和WC-Co相界处形成了空洞造成的。由于在拉伸下观察到的微缺陷数量大于在压缩下观察到的微缺陷数量，因此可以认为这是应变不对称的物理原因。此外，EBSD数据显示，在压缩和拉伸蠕变测试中，