Improvement of grain refining efficiency for Mg–Al alloy modified by the combination of carbon and calcium

Effects of Carbon and/or Alkaline Earth Elements on Grain Refinement and Tensile Strength of AZ31 Alloy

“…26,27) Judged by Fig. 1, much higher refining efficiency could be obtained for the samples of the AZ31 alloy modified by 0.2 mass%C combined with either 0.2 mass%Ca or 0.2 mass%Sr, compared to the other samples of the AZ31 alloy modified separately by 0.2 mass%C, 0.2 mass%Ca and 0.2 mass%Sr.…”

“…In the authors' previous studies, [26][27][28][29] the Al-C-O particles were observed in the samples of the Mg-3Al alloy modified either by 0.2 mass%C or by the combination of 0.2 mass%C and alkaline earth elements. In the Al-C-O particles, the alkaline earth elements were hardly detected by EDS when the addition contents of Ca or Sr were less than 0.2 mass%.…”

“…20) Recently, the authors reported that the higher grain refining efficiency could be obtained for the Mg-3Al alloy modified by the combination of carbon and alkaline earth elements Ca or Sr due to the synergistic action of more potent nuclei and higher constitutional undercooling. 26,27) In the present study, the AZ31 alloy was used and the following research works have been carried out to clarify: (1) whether the high grain refinement could also be obtained for the AZ31 alloy which was modified by the combination of carbon and alkaline earth elements Ca or Sr; (2) how mechanical properties change for the AZ31 alloy which was modified with only carbon and alkaline earth elements Ca or Sr, as well as the combination of carbon and alkaline earth elements. The ultimate purpose is that some important data were provided to develop a suitable and reliable grain refiner to be applied for the Mg-Al alloys.…”

Effect of strontium on the grain refining efficiency of Mg–3Al alloy refined by carbon inoculation

“…Therefore, it is promising that a higher grain refining efficiency could be obtained for the Mg-Al alloys if they were refined by the combination of carbon and Ca or Sr due to the synergistic action of more potential nuclei and higher constitutional undercooling. In our previous study, higher grain refining efficiency was obtained for the Mg-3Al alloy which was refined by the combination of 0.2% C and the optimal content (0.2%) of Ca [26]. However, few studies on the grain refinement of Mg-Al alloys by the combination of carbon and Sr have been conducted.…”

Effects of Grain Refining Elements on the Mechanical Properties and Mold Filling Ability of AZ91D Alloy

“…Sr첨가 미 세화 방법은 용탕의 유동성 및 인장성질의 향상에도 효과적인 것으로 확인되었으며, 알루미늄주조합금에서 쓰이는 Al-Sr 모합 금을 그대로 적용할 수 있어 실용성 측면에서도 유리할 것으로 기대된다 [8]. 한편, 알루미늄합금의 결정립 미세화제로 널리 쓰 이는 TiB과 내열성에 효과적인 Ca의 경우에도 결정립 미세화 효과가 있는 것으로 보고된 바 있다 [9][10][11]. 이처럼 비교적 실 용성이 높을 것으로 보이는 몇 가지 결정립 미세화제들의 효과 는 이미 어느 정도 알려져 있으나 상대적인 비교나 인장특성에 미치는 영향 등은 아직 충분히 조사되지 못 하였으며, 따라서 본 연구에서는 가장 널리 쓰이는 상용 주조합금인 AZ91D를 선정하였고 여기에 소량의 Sr, TiB 및 Ca을 첨가하여 결정립 미세화 효과, 유동성, 금형충전거동 및 인장특성을 종합적으로 고찰하였다.…”