Abstract: An inflator device having a chamber wherein a pressure dependant gas generant reacts to produce inflation gas and at least one orifice allowing the gas to pass and inflate an airbag. The at least one orifice is defined at least in part by a shape memory alloy having an austenite finishing temperature (Tf). The at least one orifice has a first fluid flow through area (A1) when at a temperature less than Tf and a second fluid flow through area (A2) when at a temperature greater than Tf. The second fluid flow through area (A2) is less than the first fluid flow through area (A1).