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研究了汽车发动机用铁铝合金在热震过程中裂纹的扩展情况。结果表明,在较低的热震温差作用下,Zr O2(3Y)和TF30的裂纹扩展不是很明显。随着热震温差的增加,逐渐出现裂纹的扩展,此时裂纹扩展的主要特点是扩展量小的稳态扩展。当材料的热震温差达到某一临界值时,裂纹迅速扩展贯穿整个试样表面。此时裂纹扩展呈现稳态扩展、失稳扩展和不发生扩展同时存在的特点。Fe3Al颗粒的桥联作用,消耗了裂纹尖端处的能量,能够抑制裂纹的扩展。
The crack propagation in the process of thermal shock of iron-aluminum alloy for automotive engine was studied. The results show that the crack propagation of Zr O2 (3Y) and TF30 is not obvious at lower thermal shock temperature difference. With the increase of thermal shock temperature difference, the crack propagation gradually appears. At this time, the main characteristic of crack propagation is the small steady expansion. When the thermal shock temperature difference reaches a certain critical value, the crack rapidly spreads through the entire sample surface. In this case, the crack growth shows the characteristics of steady state expansion, instability expansion and simultaneous non-expansion. The bridging effect of Fe3Al particles consumes the energy at the crack tip and suppresses the propagation of cracks.