TY - JOUR A1 - Schempp, Philipp A1 - Cross, C.E. A1 - Häcker, Ralf A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Influence of grain size on mechanical properties of aluminium GTA weld metal N2 - Grain refinement is an important possibility to enhance the mechanical properties such as strength, ductility and toughness of aluminium weld metal. In this study, grain refinement was achieved through the addition of commercial grain refiner Al Ti5B1 to gas tungsten arc weld metal of the aluminium alloys 1050A (Al 99.5) and 5083 (Al Mg4.5Mn0.7). The grain refiner additions led to a significant reduction of the weld metal mean grain size (Alloy 1050A, 86 %; Alloy 5083, 44 %) with a change in grain shape from columnar to equiaxed. Tensile tests showed for Alloy 5083 that the weld metal's ductility can be increased through grain refinement. No improvement in weld metal strength (i.e. yield strength and ultimate tensile strength) was observed. Furthermore, tear tests with notched specimens revealed that the resistance against initiation and propagation of cracks in the weld metal can be enhanced through grain refinement. The toughness was observed to increase clearly by grain refinement in weld metal of commercial pure Al (Alloy 1050A). In Alloy 5083 weld metal, the toughness was not improved through grain refinement, likely because of a semi-continuous network of brittle intermetallic phases that facilitate crack propagation. KW - GTA welding KW - Aluminium KW - Grain size KW - Tensile tests KW - Dynamic fracture tests PY - 2013 U6 - https://doi.org/10.1007/s40194-013-0026-6 SN - 0043-2288 SN - 1878-6669 VL - 57 IS - 3 SP - 293 EP - 304 PB - Springer CY - Oxford AN - OPUS4-28065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schempp, Philipp A1 - Cross, C.E. A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Influence of solute content and solidification parameters on grain refinement of aluminum weld metal N2 - Grain refinement provides an important possibility to enhance the mechanical properties (e.g., strength and ductility) and the weldability (susceptibility to solidification cracking) of aluminum weld metal. In the current study, a filler metal consisting of aluminum base metal and different amounts of commercial grain refiner Al Ti5B1 was produced. The filler metal was then deposited in the base metal and fused in a GTA welding process. Additions of titanium and boron reduced the weld metal mean grain size considerably and resulted in a transition from columnar to equiaxed grain shape (CET). In commercial pure aluminum (Alloy 1050A), the grain-refining efficiency was higher than that in the Al alloys 6082 and 5083. Different welding and solidification parameters influenced the grain size response only slightly. Furthermore, the observed grain-size reduction was analyzed by means of the undercooling parameter P and the growth restriction parameter Q, which revealed the influence of solute elements and nucleant particles on grain size. KW - Aluminium KW - GTA welding KW - Grain refinement KW - Alloy 1050A KW - Alloy 5083 KW - Alloy 6082 KW - Al Ti5B1 PY - 2013 U6 - https://doi.org/10.1007/s11661-013-1649-3 SN - 1073-5623 SN - 1543-1940 VL - 44A IS - 7 SP - 3198 EP - 3210 PB - The Minerals, Metals and Materials Society CY - Warrendale AN - OPUS4-28656 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schempp, Philipp A1 - Häcker, Ralf A1 - Pittner, Andreas A1 - Cross, C.E. A1 - Rethmeier, Michael T1 - Influence of grain size on mechanical properties of aluminium GTA weld metal N2 - Surface modification of mild steel was undertaken using two covered electrodes and two tubular electrodes. The two covered electrodes are DIN 8555: E6-UM-60 and E10-UM-60GR; however, the two tubular electrodes are E10-GF-60GR1 and E10-GF-60GR2. Chemical analysis for the weld metal and XRD of the flux covering for covered electrodes and flux core for tubular electrodes were conducted. The most important factor in determining the wear resistance is the microstructure of the deposit layers. In similar carbon equivalent electrodes E10-UM-60GR and E10-GF-60GR1, electrode E10-GF-60GR1 (tubular) shows larger carbides area fraction and better wear resistance than electrode E10-UM-60GR (covered). This could be attributed to a lower dilution associated with tubular electrode compared with covered electrode. The two tubular electrodes showed higher wear resistance than the covered electrodes which is mainly due to the larger Fe-Cr carbide precipitation area fraction. KW - GTA welding KW - Aluminium KW - Grain refinement KW - Tensile tests KW - Tear tests PY - 2014 U6 - https://doi.org/10.1007/s40194-014-0132-0 SN - 0354-7965 VL - 58 IS - 4 SP - 491 EP - 497 PB - Drustvo za Unapredjivanje Zavarivanja u Srbiji CY - Beograd AN - OPUS4-35103 LA - srp AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -