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This work investigates the effects of time dependency for isothermal sintering on additive manufactured Ni–Mn–Ga magnetic shape memory alloys. Binder jetting additive manufacturing was used to produce Ni–Mn–Ga parts from pre-alloyed powders. Additive manufacturing via the binder jetting technique produces parts with intrinsic porosities, based on the morphology of the source material. The Ni–Mn–Ga parts printed in this study using the binder jetting method possessed average densities of ~ 46% before sintering. These samples were sintered at 1353 K in increments of 10 h up to 50 h. Based on this temperature and time frame, (1) microstructural evolution, (2) crystallographic phase analysis, (3) transformation behaviors, and (4) thermal–physical properties were investigated. The additive manufactured Ni–Mn–Ga samples exhibited increases in densities, from ~ 74 to ~ 83% due to solid-state diffusion mechanisms. X-ray diffraction reveals that all of the additive manufactured samples have the 5 M martensitic phase at room temperature. Reversible martensitic transformation temperatures were recorded during heating and cooling cycles through differential scanning calorimetry, which indicate austenitic phase transformations occurring slightly above ambient temperatures. Additionally, analysis of the heating and cooling cycles prescribes that the entropy and Gibb’s energies decrease over the reversible martensitic transformations as sintering time increases. It is envisioned that this study will support a more synergistic manufacturing process between binder jetting additive manufacturing and post-heat treatment processes for Ni–Mn–Ga shape memory alloys.

Diabetes mellitus (DM) is a risk factor for surgical complications and a common comorbidity in the setting of head and neck (HN) cancer. Our objective was to determine if DM is associated with increased rates of HN cancer surgery complications.We conducted a search of Pubmed, Embase, and the national clinical trials database focusing on HN cancer surgery or free flap reconstruction and diabetes. Two reviewers screened studies by title/abstract and then full text. We then collected data using a pre-made template. Meta-analysis was performed using Revman 5.3.Of the 272 results from Pubmed and 559 from Embase, we selected 16 studies for inclusion. Meta-analysis revealed DM was associated with increased rates of flap failure (risk ratio [RR] = 1.83 95% confidence interval [CI], 1.18-2.85; P = .007) and local complications (RR = 1.87 95% CI, 1.24-2.80; P .00001).Although DM is associated with increased risk of flap failure and local HN cancer surgery complications, further research is required to optimize care in this population.