Bogdanoff Toni, Tiryakioğlu Murat
Department of Materials and Manufacturing, Jönköping University, Box 1026, 55111 Jönköping, Sweden.
School of Engineering and Technology, Jacksonville University, Jacksonville, FL 32216, USA.
Materials (Basel). 2024 Dec 4;17(23):5928. doi: 10.3390/ma17235928.
A hot isostatically pressed specimen of the A357 alloy in T6 condition has been tested for fatigue performance in situ. During testing, multiple small cracks were observed during the first cycle, both in proximity to and far from the stress concentration. These cracks have competed to form a propagating crack, forming multiple crack paths initially. Once the propagating crack has been established, it has chosen paths from multiple cracks that have opened around the tip to grow further. All small cracks observed to open have been attributed to bifilms, i.e., liquid metal damage. It is imperative to develop processes that minimize liquid metal damage to enhance the fatigue performance of aluminum alloy castings.
对处于T6状态的A357合金热等静压试样进行了原位疲劳性能测试。在测试过程中，在第一个循环中就观察到多个小裂纹，这些裂纹既靠近应力集中处，也远离应力集中处。这些裂纹相互竞争形成扩展裂纹，最初形成了多条裂纹路径。一旦扩展裂纹形成，它就会从尖端周围张开的多个裂纹中选择路径进一步扩展。观察到所有张开的小裂纹都归因于双薄膜，即液态金属损伤。必须开发出将液态金属损伤降至最低的工艺，以提高铝合金铸件的疲劳性能。
