Advancing novel Al-Mn-Cr-Zr based family of alloys tailored for powder bed fusion-laser beam process
Bharat Mehta, Karin Frisk, Lars Nyborg
Abstract
Additive manufacturing coupled with modern computational tools have enabled novel alloy design possibilities to create materials for the future. One such example is the Al-Mn-Cr-Zr based family of alloys tailored for powder bed fusion-laser beam process. This alloy system has previously been shown to produce crack free samples with good precipitation hardening response and strong thermal stability up to 523 K 2500 h. The current study investigates modifications made to enhance the mechanical response of the alloys. It was done by creating three novel alloy variants with higher Zr and addition of Mg. Interestingly, increasing Zr independently triggered grain refinement while addition of Mg independently causes significant increase in as-printed hardness albeit causing solidification cracking. Desirable properties were achieved when both higher Zr and addition of Mg was done at the same time. As-printed hardness enhanced by 30 % from previously known as-printed hardness of 102 HV to 132 HV in one of the variants. Upon direct ageing, peak hardness of 172 HV is observed thus suggesting retention of precipitation hardening.