3541 The Fatigue Strength of Ultra-fine Grained P/M Aluminum Alloys at Elevated Temperature
Details
Fatigue strength at elevated temperatures were investigated using ultra-fine grained P/M (Powder Metallurgy) aluminum alloy of which grain size was from 200 to 500nm. Reversed plane bending fatigue tests were conducted at three different temperatures of room temperature (R.T.) and 250℃ (523K), and crack initiation and small crack growth were studied in detail by means of replication technique. The effect of pre-plastic working on fatigue strength was investigated using the three kinds of P/M Al alloys which were upset forging ratios. The dependence of fatigue strength on temperature was much smaller than that of conventional Al alloys. The crack initiated at the boundary between powders regardless of forging rations.
