Ni-Mn-Ga magnetic shape memory alloy was processed by laser metal deposition, an additive manufacturing method. Powder used for deposition was crushed from a cast 10 M martensite Ni-Mn-Ga ingot. The deposited sample was ferromagnetic and showed a 14 M martensite with no detectable macroscopic composition differences throughout, except for a thin layer between substrate and deposit. Layer-by-layer deposition resulted in a layered microstructure due to differences in local thermal histories, and the sample's broad transformation temperature range is proposed to originate from the resulting variations in microstructure. Although the sample is clearly polycrystalline, columnar grains span deposition layers, which is potentially favorable to twin boundary motion. After a homogenizing and ordering heat treatment, transformations regained a typical narrow hysteresis and saturation magnetization increased, while grain growth and/or recrystallization took place. The results show the promise of laser-based additive manufacturing processes for production of magnetic shape memory alloys.

Ni-Mn-Ga磁性形状记忆合金是通过激光金属沉积（一种增材制造方法）进行加工的。从铸造的10 M马氏体Ni-Mn-Ga锭中压碎用于沉积的粉末。沉积的样品是铁磁性的，并且显示出14 M的马氏体，除了基材和沉积物之间的薄层外，整个过程中没有可检测到的宏观组成差异。由于局部热历史的差异，逐层沉积导致了分层的微观结构，并且样品的宽转变温度范围被认为是由微观结构的变化引起的。尽管样品显然是多晶的，但柱状晶粒跨越沉积层，这可能有利于孪晶边界运动。经过均质化和有序的热处理后，相变恢复了典型的窄磁滞，饱和磁化强度增加，同时发生了晶粒长大和/或重结晶。结果表明，基于激光的增材制造工艺有望生产磁性形状记忆合金。