TY - JOUR A1 - Coniglio, N. A1 - Cross, Carl Edward T1 - Mechanisms for solidification crack initiation and growth in aluminium welding N2 - In the present work, mechanisms are proposed for solidification crack initiation and growth in aluminum alloy 6060 arc welds. Calculations for an interdendritic liquid pressure drop, made using the Rappaz-Drezet-Gremaud (RDG) model, demonstrate that cavitation as a liquid fracture mechanism is not likely to occur except at elevated levels of hydrogen content. Instead, a porosity-based crack initiation model has been developed based upon pore stability criteria, assuming that gas pores expand from pre-existing nuclei. Crack initiation is taken to occur when stable pores form within the coherent dendrite region, depending upon hydrogen content. Following initiation, crack growth is modeled using a mass balance approach, controlled by local strain rate conditions. The critical grain boundary liquid deformation rate needed for solidification crack growth has been determined for a weld made with a 16 pct 4043 filler addition, based upon the local strain rate measurement and a simplified strain rate partitioning model. Combined models show that hydrogen and strain rate control crack initiation and growth, respectively. A hypothetical hydrogen strain rate map is presented, defining conceptually the combined conditions needed for cracking and porosity. KW - 6060 aluminium KW - Weld solidification cracking KW - Crack initiation/growth mechanisms KW - Transverse strain rate KW - Porosity formation PY - 2009 DO - https://doi.org/10.1007/s11661-009-9964-4 SN - 1073-5623 SN - 1543-1940 VL - 40 IS - 11 SP - 2718 EP - 2728 PB - The Minerals, Metals and Materials Society CY - Warrendale AN - OPUS4-20627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ben-Hamu, G. A1 - Eliezer, D. A1 - Cross, Carl Edward A1 - Böllinghaus, Thomas T1 - Volta potential of second phase particles in TIG welded AZ31 magnesium sheet T2 - EUROCORR 2006 CY - Maastricht, The Netherlands DA - 2006-09-25 KW - TIG welding KW - AZ31 Magnesium Alloy KW - Corrosion behavior PY - 2006 N1 - Serientitel: EFC-Event – Series title: EFC-Event IS - 280 SP - 1 EP - 10 PB - European Federation of Corrosion CY - Maastricht AN - OPUS4-22134 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Cross, Carl Edward A1 - Coniglio, Nicolas A1 - Schempp, Philipp A1 - Mousavi, M.G. ED - Lippold, J. ED - Böllinghaus, T. ED - Cross, C.E. ED - et al., T1 - Critical conditions for weld solidification crack growth N2 - The occurrence of solidification cracking during welding remains a little understood phenomenon, in spite of extensive studies and tests performed to evaluate and compare the relative weldability of many different alloys. From an approach often adopted in the welding community attributed to Prokhorov, solidification cracks are believed to form when a critical tensile strain is exceeded, specific to the alloy, assuming that the mushy-zone has limited ductility. Tensile stresses and strains normally form behind a moving weld pool as a result of solidification shrinkage and thermal contraction, as influenced by welding parameters and the degree of restraint. KW - Solidification cracking KW - Aluminium alloy KW - Crack growth KW - Strain rate model PY - 2011 SN - 978-3-642-16863-5 DO - https://doi.org/10.1007/978-3-642-16864-2_2 IS - Part 2 SP - 25 EP - 41 PB - Springer CY - Berlin, Heidelberg AN - OPUS4-23846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schempp, Philipp A1 - Cross, Carl Edward A1 - Schwenk, Christopher A1 - Rethmeier, Michael T1 - Influence of Ti and B additions on grain size and weldability of aluminium alloy 6082 N2 - Grain refinement is an important possibility to enhance the weldability of aluminium weld metal that is usually defined by its susceptibility to solidification cracking. In this study, grain refinement was achieved through the addition of commercial grain refiner containing titanium and boron to the GTA weld metal of aluminium alloy 6082. The weld metal mean grain size could be reduced significantly from about 70 µm to a saturated size of 21 µm with a change in grain shape from columnar to equiaxed. The grain refinement prevented the formation of centreline solidification cracking that was present only in welds with unrefined grain structure. A variation of torch speed led to a strong change of solidification parameters such as cooling rate that was measured in the weld metal and the corresponding solidification rate and thermal gradient. The ratio thermal gradient/growth rate (G/R) decreased from 50 K s/mm² (high torch speed) to 10 K s/mm² (low torch speed). However, the variation of torch speed did not change the tendency for solidification cracking. The microstructure of unrefined and completely refined weld metal was compared. The observed change in size and distribution of the interdendritic phases was related to the change in susceptibility to solidification cracking. KW - Aluminium KW - WIG-Schweißen KW - Kornfeinung KW - Schweißeignung KW - Heißrisse KW - Aluminium alloy KW - Solidification cracking KW - Weldability KW - GTA welding PY - 2012 SN - 0043-2288 SN - 1878-6669 VL - 56 IS - 09/10 SP - 95 EP - 104 PB - Springer CY - Oxford AN - OPUS4-26992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kannengießer, Thomas A1 - Cross, Carl Edward A1 - Böllinghaus, Thomas ED - Karl-Heinrich Grote, ED - Erik K. Antonsson, T1 - Modern Joining Technology - Weld Simulation PY - 2009 SN - 978-3-540-49131-6 IS - Part B / 7.4.8 SP - 706 EP - 723 PB - Springer AN - OPUS4-19047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Winzer, Nicholas A1 - Xu, Ping A1 - Bender, S. A1 - Gross, Thomas A1 - Unger, Wolfgang A1 - Cross, Carl Edward T1 - Stress corrosion cracking of gas-tungsten arc welds in continuous-cast AZ31 Mg alloy sheet N2 - AZ31 Mg alloy sheet was welded using a gas-tungsten arc (GTA) process over inserts containing 2.3-9.3 wt.% Al. The welded specimens were susceptible to SCC in distilled water, with susceptibility increasing with decreasing weld metal Al (or β particle) concentration. Primary stress corrosion cracks initiated at the weld metal-HAZ interface by stress-assisted localised dissolution and propagated through the weld and base metals by transgranular and intergranular H-assisted fracture (TG-HAF and IG-HAF) respectively. The IG fracture mode may be intrinsic to the texture imparted upon the base metal by rolling. The increase in SCC susceptibility with decreasing weld metal Al concentration is contrary to the purported roles of β particles in promoting localised corrosion and as crack nucleation sites, but corresponds with increases in weld - base metal galvanic current density and weld metal localised corrosion susceptibility. KW - C. Stress corrosion KW - C. Hydrogen embrittlement KW - A. Magnesium KW - C. Welding PY - 2009 DO - https://doi.org/10.1016/j.corsci.2009.05.037 SN - 0010-938X VL - 51 IS - 9 SP - 1950 EP - 1963 PB - Elsevier CY - Orlando, Fla. AN - OPUS4-20049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Babu, N. K. A1 - Cross, Carl Edward ED - Kainer, K.U. T1 - Influence of variable polarity pulsed current technique on grain refinement of AZ31 weldments T2 - Magnesium - 8th International conference on magnesium alloys and their applications CY - Weimar, Germany DA - 2009-10-26 KW - Variable polarity KW - Puulsed current welding KW - Magnesium KW - Grain refinement PY - 2009 SN - 978-3-527-32732-4 SP - 996 EP - 1003 PB - Wiley-VCH AN - OPUS4-20587 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böllinghaus, Thomas A1 - Cross, Carl T1 - Obituary: Prof. Dr.-Ing. Hans Hoffmeister N2 - On November 3, 2023, our dear colleague, Prof. Dr.-Ing. Hans Hoffmeister, born in 1932 in Kassel, Germany, passed away in Ahrensburg, near Hamburg, Germany. KW - Metals and Alloys KW - Mechanical Engineering KW - Mechanics of Materials PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594160 DO - https://doi.org/10.1007/s40194-023-01675-4 SP - 1 EP - 2 PB - Springer Science and Business Media LLC AN - OPUS4-59416 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -