For long-term applications of components, such as in turbomachinery or automotive engineering, knowledge of creep behavior under increased load and temperature is of interest. Creep tests are commonly used to investigate the creep behavior of materials at a constant test temperature above room temperature under a constant force. The present work describes a so-called uniaxial step loading creep test setup and first results for a WC-Co hard metal under isothermal conditions at 700 °C in vacuum. Heating and temperature control within the tested specimen's gauge length were performed by induced eddy currents and a thermocouple, respectively. In contrast to conventional creep tests, the mechanical load is increased stepwise and the stress at each level is kept constant for 500 s. Displacement of the strain gauge markings was measured contactless with a laser extensometer. First tests were carried out for a WC-Co hard metal under compression and tensile loading. In order to avoid buckling of the high-strength material under compression, a special specimen geometry with non-constant specimen diameter was used. The minimum creep rate was determined for each applied tensile and compressive stress level. Under tensile load, minima of the creep rate were observed above a stress of 500 MPa that are interpreted as the secondary creep rates. Under compressive load, the respective creep rate minima were observed above a stress of −700 MPa.

对于部件的长期应用（例如在涡轮机械或汽车工程中），要了解在增加的负载和温度下的蠕变行为。蠕变测试通常用于研究材料在高于恒定温度的恒定测试温度以上的恒定测试温度下的蠕变行为。本工作描述了所谓的单轴阶跃载荷蠕变测试装置，以及在真空中700°C等温条件下WC-Co硬质合金的初步结果。分别通过感应涡流和热电偶在试样长度范围内进行加热和温度控制。与常规蠕变测试相比，机械负载逐步增加，并且每个级别的应力保持恒定500 s。用激光引伸计非接触式测量应变仪标记的位移。在压缩和拉伸载荷下对WC-Co硬质金属进行了首次测试。为了避免高强度材料在压缩下发生屈曲，使用了具有非恒定试样直径的特殊试样几何形状。对于每个施加的拉伸和压缩应力水平，确定最小蠕变速率。在拉伸载荷下，在500 MPa的应力以上观察到蠕变速率达到最小值，这被解释为二次蠕变速率。在压缩载荷下，在-700 MPa应力以上观察到各自的蠕变速率最小值。使用具有非恒定样品直径的特殊样品几何形状。对于每个施加的拉伸和压缩应力水平，确定最小蠕变速率。在拉伸载荷下，在500 MPa的应力以上观察到蠕变速率达到最小值，这被解释为二次蠕变速率。在压缩载荷下，在-700 MPa应力以上观察到各自的蠕变速率最小值。使用具有非恒定样品直径的特殊样品几何形状。对于每个施加的拉伸和压缩应力水平，确定最小蠕变速率。在拉伸载荷下，在500 MPa的应力以上观察到蠕变速率达到最小值，这被解释为二次蠕变速率。在压缩载荷下，在-700 MPa应力以上观察到各自的蠕变速率最小值。