Ahlatci H. | Karakaş M.S. | Candan E. | Çimenoglu H.

Article | 2003 | Materials Science and Technology19 ( 7 ) , pp.949 - 954

In this study, dry sliding and abrasive wear behaviour of Al - 70 vol.-%Al2O3 particulate composite alloyed with Mg was examined. The composites were produced by a pressure infiltration casting technique. The composition of the matrix varied between 0 and 8 wt-%Mg, and the diameter of the Al2O3 particulates was 60 µm. Dry sliding wear tests were carried out on an unlubricated M2 quality high speed tool steel disc by a pin on disc type wear tester. Abrasive wear tests were run by rubbing the composites on abrasive Al2O3 grains. The results of the wear tests revealed that, both dry sliding and abrasive wear resistance of the composite . . .s increased with increasing Mg content in the matrix. © 2003 IoM Communications Ltd. Published by Maney for the Institute of Materials, Minerals and Mining Daha fazlası Daha az

Salamci E. | Cochrane R.F.

Article | 2003 | Materials Science and Technology19 ( 8 ) , pp.1130 - 1136

The microstructure and mechanical properties of spray deposited 7000 series aluminium alloys were investigated. The 7000 type alloys were produced by the spray atomisation deposition method. These alloys were hot extruded and subsequently heat treated in the T6 and T7 temper conditions. Microstructural characterisation of the alloys was carried out by transmission electron microscopy (TEM). TEM studies revealed the presence of ?' and ?(MgZn2) hardening precipitates in both temper conditions. The mechanical properties were assessed through tensile and notched tensile tests using an Instron machine. It was observed that the 0.2% proof . . . stress of these alloys after T7 temper decreased with increased elongation to fracture values. © 2003 IoM Communications Ltd. Published by Maney for the Institute of Materials, Minerals and Mining Daha fazlası Daha az

Gündüz S. | Cochrane R.C.

Article | 2003 | Materials Science and Technology19 ( 4 ) , pp.422 - 428

In the present work, the dynamic strain aging behaviour in microalloyed steels has been examined using a C-Mn-Al-V-N steel, which occasionally exhibits low toughness in the subcritical heat affected zone (HAZ). This may be attributed to dynamic strain aging, whereby materials show lower ductility and higher yield strength owing to the interaction between mobile dislocations and diffusing solute atoms. The research has shown that the high temperature tensile behaviour of C-Mn-Al-V-N steel depends on the presence of clusters believed to be of vanadium and carbon atoms. The interaction between dislocations and clusters of vanadium and . . .carbon atoms at 200-450°C changes the work hardening rate and contributes to dynamic strain aging as confirmed in the present work. These interactions may also decrease toughness in the subcritical HAZ and lead to the subcritical embrittlement observed in the C-Mn-Al-V-N microalloyed steel Daha fazlası Daha az