Fatigue cracking along twin boundaries has significantly different features in Cu and Cu–Al alloys. In Cu and Cu–5at%Al alloy, the twin boundaries were intrinsically strong and resist fatigue cracking. With the decrease in stacking fault energy, some fatigue cracks were observed along or near the twin boundaries in Cu–16at%Al alloys. The current findings confirmed that the twin boundaries were not always strong enough to prevent fatigue cracking, which was also affected by stacking fault energy or slip mode.

Twin Boundaries - Strong or Weak? S.Qu, P.Zhang, S.D.Wu, Q.S.Zang, Z.F.Zhang: Scripta Materialia, 2008, 59[10], 1131-4